Electromagnetic-wave shielding and light transmitting plate, manufacturing method thereof, and display panel

ABSTRACT

An electromagnetic-wave shielding and light transmitting plate  1  comprising an antireflection film  3 , an electromagnetic-wave shielding film  10 , a transparent substrate  2 , and a near-infrared ray blocking film  5 , wherein they are laminated and united by using intermediate adhesive layers  4 A,  4 B and a pressure-sensitive adhesive  4 C, and the peripheries thereof are covered by a conductive sticky tape  7 . The electromagnetic-wave shielding film  10  has a conductive foil  11  formed by pattern etching on a substrate film  13 , is processed to have antireflection function by forming a light absorbing layer  12  on the conductive foil  11 , and is subjected to a matting process to form small irregularities by roughening the surface of the light absorbing layer  12 . A display panel is manufactured by bonding this electromagnetic-wave shielding film  10  to the front surface of a plasma display panel body. Accordingly, an electromagnetic-wave shielding and light transmitting plate and a display panel can be obtained which not only have excellent electromagnetic-wave shielding function but also provide high antireflection effect and have high level of transparency and high level of visibility, thereby providing distinct images.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application of the U.S. application Ser. No.10/476,852 filed on Nov. 6, 2003, now U.S. Pat. No. 7,214,282, which isa National Stage entry of PCT/JP02/04423 filed May 7, 2002, which claimsbenefit to JP 2001-146843, JP 2001-146844, JP 2001-146845, JP2001-146846 and JP 2001-146847 all of which were filed on May 16, 2001.The prior applications are hereby incorporated by reference as if fullyset forth herein.

FIELD OF THE INVENTION

The present invention relates to an electromagnetic-wave shielding andlight transmitting plate, a manufacturing method thereof, and a displaypanel. More particularly, the present invention relates to anelectromagnetic-wave shielding and light transmitting plate which hasexcellent electromagnetic-wave shielding function, a high level oftransparency, and a high level of visibility so that it can be suitablyused as a front filter for a PDP (plasma display panel) and amanufacturing method thereof and further relates to a display panelwhich is integrally provided with an electromagnetic-wave shielding filmas mentioned above so as to add functions such as electromagnetic-waveshielding function to the display panel itself, improving theproductivity because of reduction in weight, thickness, and number ofparts of the display panel and enabling the reduction in cost.

BACKGROUND OF THE INVENTION

PDPs (plasma display panels) utilizing discharge phenomenon have beenused as display panels for television sets, office automationapparatuses such as personal computers and word processors, trafficcontrol signs, signboards, and other display boards.

The display mechanism of a PDP basically comprises two glass plates, alarge number of discharge cells formed by partitions between the twograss plates, and fluorescent substrates within the respective dischargecells. The fluorescent substrates are selectively excited to emit lightby discharge, thereby displaying characters and/or figures. An exemplaryembodiment is shown in FIG. 16. In FIG. 16, reference numeral 21designates a front glass, 22 designates a rear glass, 23 designatespartitions, 24 designates display cells (discharge cells), 25 designatesauxiliary cells, 26 designates cathodes, 27 designates display anodes,and 28 designates auxiliary anodes. Disposed in each display cell 24 isa red, green, or blue phosphor (not shown) which is a film-like formattached to the inside thereof. These fluorescent substrates emit lightby electrical discharges when a voltage is applied between electrodes.

From the front surface of the PDP, electromagnetic waves with frequencyfrom several kHz to several GHz are generated due to applying voltage,electrical discharge, and light emission. The electromagnetic waves arerequired to be shielded. In addition, for improving its displaycontrast, reflection of external light at the front surface is requiredto be prevented.

In order to shield such electromagnetic waves from PDP, conventionally,a transparent plate which has functions such as electromagnetic-waveshielding function is disposed in front of the PDP.

Electromagnetic-wave shielding material as mentioned above is alsoutilized as a window of a place where a precision apparatus isinstalled, such as a hospital or a laboratory, in order to protect theprecision apparatus from electromagnetic waves for example from cellularphones.

A conventional electromagnetic-wave shielding and light transmittingplate typically comprises transparent substrates such as acrylic boardsand a conductive mesh member like a wire netting or a transparentconductive film and is formed by interposing the conductive mesh memberor the transparent conductive film between the transparent substratesand uniting them.

A conductive mesh member which is employed in the conventionalelectromagnetic-wave shielding and light transmitting plate is a 5- to500-mesh member having a wire diameter from 10 to 500 μm and an openarea ratio (open area percentage) less than 75%. Theelectromagnetic-wave shielding and light transmitting plate employingsuch a conductive mesh member has low light transmittance of 70% at themost.

Moreover, a display comprising an electromagnetic-wave shielding andlight transmitting plate with such a conventional conductive mesh membereasily allow the production of moiré patterns due to relations betweenits patterns and pixel pitch.

As means for solving these problems, it has been proposed to use apattern-etched conductive foil as an electromagnetic-wave shieldinglayer instead of the conductive mesh (JP 2000-174491A). Anelectromagnetic-wave shielding and light transmitting plate providedwith the pattern-etched conductive foil having desired line width,distance, and mesh configuration has excellent electromagnetic-waveshielding characteristics and a high level of light transmittance andcan prevent moiré phenomenon.

The pattern etching of this conductive foil is achieved by bonding ametal foil onto a surface of a transparent substrate film, attaching aphotoresist film to the metal foil with pressure, and etching into apredetermined pattern through pattern exposure and etching steps.Accordingly, the metal foil is provided as a film laminated on thesubstrate film.

An electromagnetic-wave shielding film comprising such a laminated filmof the metal foil/the substrate film can not have sufficient visibilitybecause light is reflected at the surface of the metal foil.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide anelectromagnetic-wave shielding and light transmitting plate which notonly has excellent electromagnetic-wave shielding function but alsoprovides high antireflection effect and has a high level of transparencyand a high level of visibility.

It is another object of the present invention to provide a display panelemploying an electromagnetic-wave shielding film which not only hasexcellent electromagnetic-wave shielding function but also provides highantireflection effect and has a high level of transparency and a highlevel of visibility.

An electromagnetic-wave shielding and light transmitting plate accordingto the first aspect of the present invention is an electromagnetic-waveshielding and light transmitting plate having at least anelectromagnetic-wave shielding film and a transparent substrate whichare laminated and united, wherein the electromagnetic-wave shieldingfilm comprising a transparent substrate film and a conductive foil whichis formed by pattern etching and is bonded to the transparent substrateside surface of the substrate film with a transparent adhesive agent,the foil has a light absorbing layer for antireflection on the substratefilm side surface thereof, and the substrate film side surface of thelight absorbing layer is treated by surface roughening.

In the electromagnetic-wave shielding film, small irregularities areformed in the surface of the light absorbing layer by the surfaceroughening (hereinafter, the surface roughening will be sometimesreferred to as “matting process”) so as to provide high antireflectioneffect. Therefore, by applying the electromagnetic-wave shielding andlight transmitting plate with this electromagnetic-wave shielding filmto a front surface of a display, the display can provide a distinctimage having high contrast.

The electromagnetic-wave shielding film comprising the pattern-etchedconductive foil, the matted light absorbing layer, and the substratefilm is manufactured by the following steps:

(1) forming a light absorbing layer on the surface of the metallic foiland treating a surface of the light absorbing layer by surfaceroughening;

(2) bonding the metallic foil obtained by the above (1) to a transparentsubstrate film by transparent adhesive agent; and

(3) pattern-etching the laminated body obtained by the above (2).

In the bonding step of the above (2), the irregularities of the surfaceof the matted light absorbing layer are transferred to the transparentadhesive layer. Therefore, the surface of the transparent adhesive layerexposed after etching and removing the light absorbing layer and themetallic foil by pattern etching has irregularities transferred from thelight absorbing layer.

The irregularities of the transparent adhesive layer have lightscattering property. Accordingly, in the present invention, as claimedin claim 2 or 5, it is preferable that the irregularities transferred tothe transparent adhesive layer is filled with thermosetting resin ortransparent pressure-sensitive adhesive by bonding the foil side surfaceof the electromagnetic-wave shielding film to the transparent substratewith the thermosetting resin or the transparent pressure-sensitiveadhesive, thereby preventing the light scattering and thus improving thetransparency.

An electromagnetic-wave shielding and light transmitting plate accordingto the second aspect of the present invention is an electromagnetic-waveshielding and light transmitting plate having at least anelectromagnetic-wave shielding film and a transparent substrate whichare laminated and united, wherein the electromagnetic-wave shieldingfilm comprising a transparent substrate film and a conductive foil whichis formed by pattern etching and is bonded to a surface opposite to thetransparent substrate side surface of the substrate film with atransparent adhesive agent, the foil has a light absorbing layer forantireflection on a surface opposite to the substrate film side surfacethereof, and the surface opposite to the substrate film side surface ofthe light absorbing layer is treated by surface roughening.

Also in the electromagnetic-wave shielding film, the surface of thelight absorbing layer is treated by the surface roughening so as toprovide high antireflection effect. Therefore, by applying theelectromagnetic-wave shielding and light transmitting plate with thiselectromagnetic-wave shielding film to a front surface of a display, thedisplay can provide a distinct image having high contrast.

The electromagnetic-wave shielding film comprising the matted lightabsorbing layer, the pattern-etched conductive foil, and the substratefilm is manufactured by the following steps:

(i) bonding the metallic foil to the transparent substrate film bytransparent adhesive agent;

(ii) pattern-etching a laminated body obtained by the above (i); and

(iii) forming a light absorbing layer on the surface of thepattern-etched metallic foil and treating a surface of the lightabsorbing layer by surface roughening.

A manufacturing method of an electromagnetic-wave shielding and lighttransmitting plate according to the third aspect of the presentinvention is a method of manufacturing the electromagnetic-waveshielding and light transmitting plate by laminating and uniting atleast an electromagnetic-wave shielding film and a transparent substrateand is characterized by comprising: a step of forming a light absorbinglayer on one surface of a conductive foil; a step of treating a surfaceof the light absorbing layer by surface roughening; a step of bondingthe conductive foil with the light absorbing layer to a transparentsubstrate film by transparent adhesive agent; a step of pattern etchingthe conductive foil with the light absorbing layer bonded on thesubstrate film; a step of forming a coating layer by applying atransparent pressure-sensitive adhesive on the etched surface of theelectromagnetic-wave shielding film obtained by the pattern etching; anda step of attaching the coating layer of the electromagnetic-waveshielding film to the transparent substrate with some pressure so as tolaminate and unite the electromagnetic-wave shielding film and thetransparent substrate.

In this method, the electromagnetic-wave shielding film comprising thepattern-etched conductive foil, the matted light absorbing layer, andthe substrate film is manufactured by the aforementioned steps (1)-(3).As mentioned above, the surface of the transparent adhesive layerexposed after etching and removing the light absorbing layer and themetallic foil by pattern etching has irregularities transferred from thelight absorbing layer.

The irregularities of the transparent adhesive layer have lightscattering property. According to the present invention, theirregularities transferred to the transparent adhesive layer is filledwith transparent pressure-sensitive adhesive by applying the transparentpressure-sensitive adhesive to the foil side surface of theelectromagnetic-wave shielding film, thereby preventing the lightscattering and thus improving the transparency.

In this case, the transparent pressure-sensitive adhesive allowsre-adhesion and can bond strongly the electromagnetic-wave shieldingfilm and the transparent substrate or the like together withoutcapturing air bubbles between their boundary faces.

The thickness of the coating layer of the transparent pressure-sensitiveadhesive is preferably from 1 to 100 μm. The coating layer having such athickness can absorb the irregularities of the matted surface of thelight absorbing layer and has a good workability for bonding theelectromagnetic-wave shielding film to the transparent substrate or thelike.

The electromagnetic-wave shielding film may be bonded to the transparentsubstrate via another film. However, it is preferable that theelectromagnetic-wave shielding film is directly bonded to thetransparent substrate with transparent pressure-sensitive adhesive.

A display panel according to the fourth aspect of the present inventionis a display panel comprising a display panel body and anelectromagnetic-wave shielding film disposed on the front surface of thedisplay panel body, wherein the electromagnetic-wave shielding filmcomprises a transparent substrate film and a conductive foil which isformed by pattern etching and is bonded to the display panel body sidesurface of the substrate film with a transparent adhesive agent, thefoil has a light absorbing layer for antireflection on the substratefilm side surface thereof, and the substrate film side surface of thelight absorbing layer is treated by surface roughening.

A display panel according to the fifth aspect of the present inventionis a display panel comprising a display panel body and anelectromagnetic-wave shielding film disposed on the front surface of thedisplay panel body, wherein the electromagnetic-wave shielding filmcomprises a transparent substrate film and a conductive foil which isformed by pattern etching and is bonded to a surface opposite to thedisplay panel body side surface of the substrate film with a transparentadhesive agent, the foil has a light absorbing layer for antireflectionon a surface opposite to the substrate film side surface thereof, andthe surface opposite to the substrate film side surface of the lightabsorbing layer is treated by surface roughening.

These display panels are each formed by disposing anelectromagnetic-wave shielding film on a front surface of a displaypanel body, thereby achieving the reduction in weight, thickness, andthe number of parts of the display panel, leading to the improvement ofthe productivity and reducing the cost.

In the electromagnetic-wave shielding film, small irregularities areformed in the surface of the light absorbing layer by the surfaceroughening so as to provide high antireflection effect. Therefore, byapplying this electromagnetic-wave shielding film to a front surface ofa display panel body, the display can provide a distinct image havinghigh contrast.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing an embodiment of anelectromagnetic-wave shielding and light transmitting plate according tothe first aspect;

FIG. 2 is a schematic sectional view showing another embodiment of anelectromagnetic-wave shielding and light transmitting plate according tothe first aspect;

FIGS. 3A-3F are explanatory illustrations showing an exemplary method ofmanufacturing an electromagnetic-wave shielding film to be used in thefirst aspect;

FIGS. 4A-4F are plan views showing concrete examples of etchingpatterns;

FIG. 5 is an enlarged sectional view for explaining a bonding portionbetween the electromagnetic-wave shielding film and a transparentsubstrate of the electromagnetic-wave shielding and light transmittingplate of FIG. 1;

FIG. 6 is a schematic sectional view showing an embodiment of anelectromagnetic-wave shielding and light transmitting plate according tothe second aspect;

FIGS. 7A-7F are explanatory illustrations showing an exemplary method ofmanufacturing an electromagnetic-wave shielding film used in the secondaspect;

FIG. 8 is an enlarged sectional view for explaining a bonding portionbetween the electromagnetic-wave shielding film and a transparentsubstrate of the electromagnetic-wave shielding and light transmittingplate of FIG. 6;

FIG. 9 is a schematic sectional view showing an embodiment of anelectromagnetic-wave shielding and light transmitting plate according tothe third aspect;

FIGS. 10A-10G are explanatory illustrations showing an exemplary methodof manufacturing an electromagnetic-wave shielding film used in thethird aspect;

FIG. 11 is an enlarged sectional view for explaining a bonding portionbetween the electromagnetic-wave shielding film with adhesive layer anda transparent substrate of the electromagnetic-wave shielding and lighttransmitting plate of FIG. 9;

FIG. 12 is a schematic sectional view showing an embodiment of a displaypanel according to the fourth aspect;

FIG. 13 is a schematic sectional view showing an embodiment of a displaypanel according to the fifth aspect;

FIG. 14 is an enlarged sectional view for explaining a bonding portionbetween the electromagnetic-wave shielding film and another member ofthe display panel of FIG. 12;

FIG. 15 is an enlarged sectional view for explaining a bonding portionbetween the electromagnetic-wave shielding film and another member ofthe display panel of FIG. 13; and

FIG. 16 is a partially cut-away perspective view showing the structureof a typical PDP.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described in detail withreference to the attached drawings.

With reference to FIGS. 3A-3F, an exemplary method of manufacturing anelectromagnetic-wave shielding film to be used in anelectromagnetic-wave shielding and light transmitting plate of the firstaspect of the present invention will be described.

For example, a copper foil 11 is prepared as a conductive foil (FIG. 3A)and a light absorbing layer 12 is formed on one surface of the copperfoil 11 (FIG. 3B). As a forming method of this light absorbing layer 12,there is a method of making a film of a copper alloy such as Cu—Ni and,after that, blackening a surface of the film by treatment with acid oralkali. The blackened surface subjected to this surface treatment isroughened. The surface roughness Rz can be controlled according to thetreatment condition. Alternatively, the light absorbing layer 12 can beformed by applying a light absorbing ink onto the copper foil 11 andhardening the ink. Examples of the light absorbing ink used here includecarbon ink, nickel ink, and inks such as dark color organic pigments.Then, the light absorbing layer 12 is subjected to a matting process toform small irregularities by mechanically roughening, for example, shotblasting the surface 12A thereof or chemically roughening the surface12A using acid or alkali, alternatively, by applying the ink which ispreviously mixed with the inorganic or organic fine particles so as toform a film originally having roughened surface (FIG. 3C). The thicknessof the light absorbing layer 12 varies depending on the blackeningmaterial and/or the conductivity, but it is preferable that thethickness is in a range from 1 nm to 10 μm in order to have sufficientelectromagnetic-wave shielding property without losing its conductivity.The level of roughness of the surface 12A is preferably in a range from0.1 to 20 μm as surface roughness Rz in order to sufficiently preventthe light scattering. The matting process is carried out such that thesurface roughness Rz of the light absorbing layer becomes 0.1-20 μm,thereby providing high antireflection effect.

After that, the copper foil 11 on which the light absorbing layer 12 isformed and treated by the matting process to have a matte surface isbonded at its matte surface side to a transparent substrate film such asa PET (polyethylene terephthalate) film 13 with a transparent adhesiveagent 14 (FIG. 3D, FIG. 3E).

Pattern etching is conducted on the thus obtained laminated filmaccording to the normal method, whereby the copper foil 11 with thelight absorbing layer 12 formed thereon is partially removed so as toobtain a copper/PET laminated etched film 10 as the electromagnetic-waveshielding film (FIG. 3F).

Exposed surface 14A of the transparent adhesive agent 14 of thecopper/PET laminated etched film 10 has irregularities corresponding tothe small irregularities, formed by the matting process, of the lightabsorbing layer 12.

The conductive foil composing the electromagnetic-wave shielding film isnot limited to copper foil and may be a foil of stainless steel,aluminum, nickel, iron, brass, or alloy thereof. Among these, copperfoil, stainless steel foil, and aluminum foil are preferable.

Since too thin metal foil is not preferable in view of the handlingproperty and the workability of pattern etching and too thick metal foilis also not preferable because it undesirably increases the thickness ofan obtained electromagnetic-wave shielding and light transmitting plateand lengthens the time required for the etching process, the thicknessof the metal foil is preferably in a range from 1 to 200 μm.

The method of pattern etching for the metal foil may be any of widelyused methods. Photo etching using a resist is preferable. In this case,a photoresist film is attached to the metal foil with pressure or aphotoresist is applied by coating, and a pattern is then exposed byusing a desired mask or the like and, after that, is developed bydeveloping process, thereby forming a resist pattern. Portions of themetal foil not covered by the resist are removed with etchant such asferric chloride solution.

The method using the photoresist film is preferable because thephotoresist film, the metal foil with the light absorbing layer formedthereon and treated by the matting process, the adhesive sheet oftransparent adhesive agent, and the substrate film are laminated in theorder of the substrate film/the adhesive sheet/the metal foil/thephotoresist film and bonded together with pressure, whereby these can belaminated and united only in one step.

According to the pattern etching, the degree of freedom of pattern ishigh so that the metal foil can be etched into a pattern having any linewidth, any distance, and any hole shape, thereby easily forming anelectromagnetic-wave shielding film capable of providing desiredelectromagnetic-wave shielding function and light transmittance withoutmoiré phenomenon.

There is no particular limitation on the configuration of the etchingpattern of the metal foil. The etching pattern may be a metal foil 11 aor 11 b formed with rectangular holes M as shown in FIGS. 4A, 4B, ametal foil 11 c, 11 d, 11 d, 11 e, or 11 f formed in a punchedmetal-like shape with circular, hexagonal, triangular or oval holes M asshown in FIGS. 4C, 4D, 4E, 4F. Instead of the pattern having regularlyarranged holes M, a random pattern may be employed to prevent the moiréphenomenon.

In order to ensure both the electromagnetic-wave shielding function andthe light transmittance, the ratio of open area to the projected area(hereinafter, referred to as “open area ratio”) of the conductive meshmember is preferably in a range from 20% to 90%.

The transparent substrate film to which the metal foil such as thecopper foil 11 is bonded may be a resin film as will be described below,besides the PET film 13, as a transparent substrate material to be usedin the electromagnetic-wave shielding and light transmitting plate ofthe present invention. Preferable examples include PET, PBT(polybutylene terephthalate), PC, PMMA, and acrylic film. The thicknessof the film is preferably set in a range from 1 μm to 200 μm to preventthe thickness of the resultant electromagnetic-wave shielding and lighttransmitting plate from being too thick and to ensure its enoughdurability and its easy handling.

As the transparent adhesive agent bonding the transparent substrate filmand the metal foil, EVA or PVB resin as the adhesive resin to be used inthe electromagnetic-wave shielding and light transmitting plate as willbe described below may be employed. The method of forming the resin intosheet and the bonding method and its condition may be the same as theadhesive resin to be used in the electromagnetic-wave shielding andlight transmitting plate. In addition, a transparent adhesive agent ofepoxy resin series, acrylic resin series, urethane resin series,polyester resin series, or rubber series may also be employed. In viewof etching resistance during the etching process after lamination,urethane resin series and epoxy resin series are particularlypreferable. The thickness of the adhesive layer of the transparentadhesive agent 14 is preferably in a range from 1 μm to 50 μm. Thetransparent adhesive agent 14 may contain conductive particle as will bedescribed later if required.

With reference to FIGS. 1 and 2, embodiments of the electromagnetic-waveshielding and light transmitting plate according to the first aspectwill be described in detail.

FIGS. 1 and 2 are schematic sectional views showing embodiments of theelectromagnetic-wave shielding and light transmitting plates accordingto the first aspect of the present invention.

The electromagnetic-wave shielding and light transmitting plate 1 ofFIG. 1 comprises an antireflection film 3 as the front-most layer, acopper/PET laminated etched film 10 as the electromagnetic-waveshielding film, a transparent substrate 2, and a near-infrared rayblocking film 5 as the rear-most layer, wherein they are laminated andunited by using intermediate adhesive layers 4A, 4B andpressure-sensitive adhesive 4C so as to form a laminated body. Aconductive sticky tape 7 (hereinafter, referred to as “second conductivesticky tape”) is bonded to cover the peripheral ends of the laminatedbody and margins along the edges of the front surface and the rearsurface thereof near the peripheral ends thereof. The size of theelectromagnetic-wave shielding film 10 is substantially equal to thesize of the transparent substrate 2 and a conductive sticky tape 8(hereinafter, referred to as “first conductive sticky tape”) is bondedto and wound around the peripheral ends of the electromagnetic-waveshielding film 10 to extend from one surface to the other surface of theelectromagnetic-wave shielding film 10.

An electromagnetic-shielding and light transmitting plate 1A of FIG. 2has the same structure as the electromagnetic-shielding and lighttransmitting plate of FIG. 1 except that transparent pressure-sensitiveadhesive 4D is used instead of the intermediate adhesive layer 4B.

The electromagnetic-shielding and light transmitting plate 1A of FIG. 2comprises an antireflection film 3 as the front-most layer, a copper/PETlaminated etched film 10 as the electromagnetic-wave shielding film, atransparent substrate 2, and a near-infrared ray blocking film 5 as therear-most layer, wherein they are laminated and united by using anintermediate adhesive layer 4A, transparent pressure-sensitive adhesive4D, and pressure-sensitive adhesive 4C so as to form a laminated body. Aconductive sticky tape 7 (second conductive sticky tape) is bonded tocover the peripheral ends of the laminated body and margins along theedges of the front surface and the rear surface thereof near theperipheral ends thereof. The size of the electromagnetic-wave shieldingfilm 10 is substantially equal to the size of the transparent substrate2 and a conductive sticky tape 8 (first conductive sticky tape) isbonded to and wound around the peripheral ends of theelectromagnetic-wave shielding film 10 to extend from one surface to theother surface of the electromagnetic-wave shielding film 10.

In FIGS. 1 and 2, the first conductive sticky tape 8 is preferablyarranged all around the peripheries of the electromagnetic-waveshielding film 10. However, the first conductive sticky tape may bearranged partially, for example, may be arranged only on two peripheriesopposite to each other.

In the electromagnetic-wave shielding and light transmitting plate 1,1A, the antireflection film 3 and the intermediate adhesive layer 4Aunder the antireflection film 3 are slightly smaller than theelectromagnetic-wave shielding film 10 and the transparent substrate 2so that the peripheries of the antireflection film 3 and theintermediate adhesive layer 4A are slightly (preferably by 3-20 mm,particularly 5-10 mm) back off from the peripheries of theelectromagnetic-wave shielding film 10 or the transparent substrate 2 sothat the first conductive sticky tape 8 arranged around the peripheriesof the electromagnetic-wave shielding film 10 is not covered by theantireflection film 3 or the intermediate adhesive layer 4A. Therefore,the second conductive sticky tape 7 is directly attached to the firstconductive sticky tape 8, thereby securing the electric continuity ofthe electromagnetic-wave shielding film 10 through the first and secondconductive sticky tapes 8, 7.

The near-infrared ray blocking film 5 with the pressure-sensitiveadhesive 4C is also slightly smaller than the transparent substrate 2 sothat the peripheries of the near-infrared ray blocking film 5 with thepressure-sensitive adhesive 4C are slightly (preferably by 3-20 mm,particularly 5-10 mm) back off from the peripheries of the transparentsubstrate 2.

In these embodiments, none of the peripheries of the antireflection film3, the intermediate adhesive layer 4A, and the near-infrared rayblocking film 5 with the pressure-sensitive adhesive 4C is covered bythe second conductive sticky tape 7. However, these may be locatedinside of and covered by the second conductive sticky tape 7. In theelectromagnetic-wave shielding and light transmitting plates 1 and 1A ofFIGS. 1 and 2, it is necessary to establish the electric continuitybetween the first conductive sticky tape 8 and the second conductivesticky tape 7. Therefore, the antireflection film 3 and the intermediateadhesive layer 4A must be smaller than the electromagnetic-waveshielding film 10 and the transparent substrate 2 so that theirperipheries are thus back off from the peripheries of theelectromagnetic-wave shielding film 10 or the transparent substrate 2.On the other hand, the near-infrared ray blocking film 5 with thepressure-sensitive adhesive 4C may have the same size as the transparentsubstrate 2.

It is preferable that all peripheries of the antireflection film 3 andthe intermediate adhesive layer 4A are preferably back off from theperipheries of the electromagnetic-wave shielding film 10 or thetransparent substrate 2. However, when the first conductive sticky tape8 is attached to only a part of the peripheries, for example, twoperipheries opposite to each other, only the corresponding peripheriesof the antireflection film 3 and the intermediate adhesive layer 4A maybe back off from the corresponding peripheries of theelectromagnetic-wave shielding film 10 or the transparent substrate 2and the second conductive sticky tape 7 may be attached to only thecorresponding peripheries.

Examples of material of the transparent substrate 2 include glass,polyester, polyethylene terephthalate (PET), polybutylene terephthalate,polymethyl methacrylate (PMMA), acrylic board, polycarbonate (PC),polystyrene, triacetate film, polyvinyl alcohol, polyvinyl chloride,polyvinylidene chloride, polyethylene, ethylene-vinyl acetate copolymer,polyvinylbutyral, metal ionic cross-linked ethylene-methacrylic acidcopolymer, polyurethane, and cellophane. Among these examples, glass,PET, PC, and PMMA are preferable.

The thickness of the transparent substrate 2 may be suitably determinedin accordance with requirements (e.g. strength, light weight) due to theapplication of the plate and is normally preferably in a range from 0.1to 10 mm, particularly 1 to 4 mm.

Acrylic resin-based black painting may be provided in a flame shape onthe peripheral portion of the transparent substrate 2.

The transparent substrate 2 may be subjected to heat ray reflectioncoating such as metallic thin layer or transparent conductive layer toimprove its function.

The antireflection film 3 may have a base film 3A having a thickness of25-250 μm such as PET, PC, and PMMA and an antireflection layer 3Bformed thereon. The antireflection layer 3B may be a single layer orlaminated layers consisting of a high-refractive transparent layer and alow-refractive transparent layer. An example of the single layer is thefollowing (1) and examples of the laminated layers are the following(2)-(5):

(1) a layer consisting of a lower-refractive transparent layer than thebase film 3A;

(2) laminated layers consisting of a high-refractive transparent layerand a low-refractive transparent layer, i.e. two layers in amount;

(3) laminated layers consisting of two high-refractive transparentlayers and two low-refractive transparent layers which are alternatelylaminated, i.e. four layers in amount;

(4) laminated layers consisting of a medium-refractive transparentlayer, a high-refractive transparent layer, and a low-refractivetransparent layer which are laminated in this order, i.e. three layersin amount; and

(5) laminated layers consisting of three high-refractive transparentlayers and three low-refractive transparent layers which are alternatelylaminated, i.e. six layers in amount.

The high-refractive transparent layer is a thin layer, preferably atransparent conductive layer, having a refractive index not lower than1.8 consisting of ITO (tin indium oxide), ZnO, or Al-doped ZnO, TiO₂,SnO₂, or ZrO. The high-refractive transparent layer may be made bydispersing particles of any aforementioned material into acrylic binderor polyester binder.

The low-refractive transparent layer can be made of low-refractivematerial having a refractive index not greater than 1.6 such as SiO₂,MgF₂, or Al₂O₃. The low-refractive transparent layer may consist oforganic material such as silicone or fluorine.

The thickness of each layer may be determined according to the filmstructure, the film kind, and the central wavelength because therefractive index in a visible-light range is reduced by interference oflight. In case of four-layer structure, the antireflection film may havethe first layer (high-refractive transparent layer) of 5 to 50 nm, thesecond layer (low-refractive transparent layer) of 5 to 50 nm, the thirdlayer (high-refractive transparent layer) of 50 to 100 nm, and thefourth layer (low-refractive transparent layer) of 50 to 150 nm inthickness.

The antireflection film 3 may be further have an antifouling layer toimprove the fouling resistance of the surface. The antifouling layer ispreferably a fluorocarbon or silicone layer having a thickness in arange from 1 to 100 nm.

The near-infrared ray blocking film 5 has a base film 5A and a coatinglayer or a multi coating layer 5B on the surface of the base film 5A.The coating layer 5B may be made of a near infrared ray absorbingmaterial such as copper inorganic material, copper organic material,cyanine, phthalocyanine, nickel complex, diimmonium. The multi coatinglayer 5B may consist of an inorganic dielectric material such as zincoxide or ITO (tin indium oxide) and a metal such as silver. The basefilm 5A may be made of PET, PC, PMMA or the like. The thickness of thebase film 5A is preferably in a range between 10 μm and 1 mm to preventthe thickness of the resultant electromagnetic-wave shielding and lighttransmitting plate from being too thick to ensure its easy handling andits durability. The thickness of the near-infrared ray blocking layer5B, which is formed on the base film 5A, is usually from 0.5 to 50 μm.

The near-infrared ray blocking layer may be made of two or more ofdifferent materials or made by mixing or laminating two or more ofcoating layers. Two near-infrared ray blocking layers may be formed onthe both surface of the base film. Two or more of near-infrared rayblocking layers may be laminated.

Not to lose the transparency and to obtain good near infrared rayblocking capability (for example, absorbing sufficiently near infraredrays in a wide near infrared wave-length range of 850 to 1,250 nm), itis preferable to use a combination of two or more of near-infrared rayblocking materials of different near-infrared ray blocking types asfollows:

(a) a coating layer made of ITO having a thickness from 100 Å to 5000 Å;

(b) a coating layer made of an alternative lamination of ITO and silverhaving a thickness from 100 Å to 10000 Å;

(c) a coating layer having a thickness from 0.5 to 50 microns andcontaining a mixture of a nickel complex and immonium which is preparedwith using a suitable transparent binder;

(d) a coating layer having a thickness from 10 to 10000 microns made byforming a film from a copper compound including bivalent copper ion witha suitable transparent binder; and

(e) a coating layer having a thickness from 0.5 to 50 microns made oforganic pigment.

Among these, it is preferable, but not limited to, to use

a combination of (a) and (c),

a combination of (a) and (d),

a combination of (b) and (c),

a combination of (b) and (d), or

(c) alone.

According to the present invention, in addition to the near-infrared rayblocking film 5, a transparent conductive film may be laminated. In thiscase, as the transparent conductive film, a resin film in whichconductive particles are dispersed or a base film on which a transparentconductive layer is formed may be employed.

The conductive particles to be contained in the film may be anyparticles having conductivity and the following are examples of suchconductive particles.

(i) carbon particles or powder;

(ii) particles or powder of metal such as nickel, indium, chromium,gold, vanadium, tin, cadmium, silver, platinum, aluminum, copper,titanium, cobalt, or lead, alloy thereof, or conductive oxide thereof;

(iii) particles made of plastic such as polystyrene and polyethylene,which are surfaced with coating layer of a conductive material from theabove (i) and (ii); and

(iv) a body formed by alternatively laminating ITO and silver.

Because the conductive particles of too large particle diameter affectthe light transparency and the thickness of the transparent conductivefilm, it is preferable that the particle diameter is 0.5 mm or less. Thepreferable particle diameter of the conductive particles is between 0.01and 0.5 mm.

Too high mixing ratio of the conductive particles in the transparentconductive film spoils the light transparency, while too low mixingratio makes the electromagnetic-wave shielding function poor. The mixingratio of the conductive particles is therefore preferably between 0.1and 50% by weight, particularly between 0.1 and 20% by weight and moreparticularly between 0.5 and 20% by weight, relative to the resin of thetransparent conductive film.

The color and the luster of the conductive particles can be suitablyselected according to the application. In a case of a filter for adisplay panel, conductive particles having a dark color such as black orbrown and dull surfaces are preferable. In this case, the conductiveparticles can suitably adjust the light transmittance of the filter soas to make the display easy-to-see.

Such a transparent conductive layer on the base film may be made of tinindium oxide, zinc aluminum oxide, or the like by one of methodsincluding vapor deposition, sputtering, ion plating, and CVD (chemicalvapor deposition). In this case, when the thickness of the transparentconductive layer is less than 0.01 μm, sufficient electromagnetic-waveshielding function can not be obtained, because the thickness of theconductive layer for the electromagnetic-wave shielding is too thin, andwhen exceeding 5 μm, light transparency may be spoiled.

Examples of the matrix resin of the transparent conductive film or theresin of the base film include polyester, PET, polybutyleneterephthalate, PMMA, acrylic board, PC, polystyrene, triacetate film,polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride,polyethylene, ethylene-vinyl acetate copolymer, polyvinylbutyral, metalionic cross-linked ethylene-methacrylic copolymer, polyurethane, andcellophane. Preferably selected from the above resins are PET, PC, andPMMA.

The thickness of the transparent conductive film is normally preferablyin a range from 1 μm to 5 mm.

Preferably used as thermosetting adhesive resin forming the intermediateadhesive layers 4A, 4B of the electromagnetic-wave shielding and lighttransmitting plate 1 of FIG. 1 for bonding the antireflection film 3,the electromagnetic-wave shielding film 10, and the transparentsubstrate 2 or forming the intermediate adhesive layer 4A of theelectromagnetic-wave shielding and light transmitting plate 1A of FIG. 2is transparent and elastic adhesive resin as ordinarily used forlaminated glass. Particularly, because the intermediate adhesive layers4A, 4B are positioned ahead of the transparent substrate 2, the elasticresin preferably having high elasticity and thus having high capabilityof preventing the scattering of fragments is effectively used.

Examples of adhesive resins having such high elasticity includecopolymers of ethylene group, such as ethylene-vinyl acetate copolymer,ethylene-methyl acrylate copolymer, ethylene-(meth) acrylic acidcopolymer, ethylene-ethyl (meth) acrylic acid copolymer, ethylene-methyl(meth) acrylic acid copolymer, metal ionic cross-linked ethylene-(meth)acrylic acid copolymer, partial saponified ethylene-vinyl acetatecopolymer, calboxylated ethylene-vinyl acetate copolymer,ethylene-(meth) acrylic-maleic anhydride copolymer, and ethylene-vinylacetate-(meth) acrylate copolymer. It should be noted that “(meth)acrylic” means “acrylic or methacrylic”. Besides the above resins,polyvinyl butyral (PVB) resin, epoxy resin, acrylic resin, phenol resin,silicone resin, polyester resin, or urethane resin may also be employed.Ethylene-vinyl acetate copolymer (EVA) can offer the best balance ofperformance and is easy to be handled. In terms of the impactresistance, the perforation resistance, the adhesive property, and thetransparency, PVB resin often used for laminated safety glasses forautomobile is also preferable.

It is preferable that the PVB resin contains polyvinyl acetal between 70and 95% by unit weight and polyvinyl acetate between 1 and 15% by unitweight, and has an average degree of polymerization between 200 and3000, preferably 300 and 2500. The PVB resin is used as resincomposition containing plasticizer.

Examples of plasticizer in the PVB resin composition include organicplasticizers, such as monobasic acid ester and polybasic acid ester, andphosphoric acid plasticizers.

Preferable examples of such monobasic acid ester are ester as a resultof reaction of organic acid, such as butyric acid, isobutyric acid,caproic acid, 2-ethylbutyric acid, heptoic acid, n-octyl acid,2-ethylhexyl acid, pelargonic acid (n-nonyl acid), or decyl acid, andtriethylene glycol and, more preferably, aretriethylene-di-2-ethylbthyrate, triethylene glycol-di-2-ethylhexoate,triethylene glycol-di-caproate, and triethylene glycol-di-n-ocotoate.Ester of one of the above organic acids and tetraethylene glycol ortripropylene glycol may be also employed.

Preferable examples of plasticizers of polybasic acid ester group areester of organic acid, such as adipic acid, sebacic acid, or azelaicacid, and straight chain like or brunch like alcohol with from 4 to 8carbon atoms and, more preferably, are dibutyl sebacate, dioctylazelate, and dibutyl carbitol adipate.

Examples of phosphoric acid plasticizers include tributoxyethylphosphate, isodecyl phenyl phosphate, and tri-isopropyl phosphate.

Insufficient plasticizer in the PVB resin composition reduces thefilm-forming property, while excessive plasticizer spoils the durabilityduring high temperature. Therefore, the amount of plasticizer in the PVBresin composition is between 5 and 50 parts by weight, preferablybetween 10 and 40 parts by weight, per 100 parts by weight of polyvinylbutyral resin.

The PVB resin composition may further include another additive agent forpreventing degradation such as stabilizer, antioxidant, and ultravioletabsorbing agent.

The adhesive resin for the intermediate adhesive layers 4A, 4B ispreferably cross-linked thermosetting resin containing cross linkingagent, especially preferably cross-linked EVA (ethylene-vinyl acetatecopolymer).

Hereinafter, the cross-linked EVA as the adhesive resin will bedescribed in detail.

As EVA, EVA including vinyl acetate in an amount of 5-50% by weight,preferably 15-40% by weight, is employed. Less than 5% by weight ofvinyl acetate interferes with the weatherability and the transparency,while exceeding 40% by weight of vinyl acetate significantly reducesmechanical characteristics, makes the film formation difficult, andproduces a possibility of blocking between films.

As the crosslinking agent, organic peroxide is preferable. The organicperoxide is selected according to the temperature for sheet process, thetemperature for crosslinking, and the storage stability. Examples ofavailable peroxide include 2,5-dimethylhexane-2,5-dihydro peroxide;2,5-dimethyl-2,5-di(t-butyl-peroxy)-hexane-3; di-t-butyl peroxide;t-butylcumyl peroxide; 2,5-dimethyl-2,5-di(t-butyl-peroxy)-hexane;dicumyl peroxide; α,α′-bis(t-butyl peroxy isopropyl)-benzene;n-buthyl-4,4-bis(t-butyl-peroxy)-valerate;2,2-bis(t-butyl-peroxy)-butane, 1,1-bis(t-butyl-peroxy)-cyclohexane;1,1-bis(t-butyl-peroxy)-3,3,5-trimethylcyclohexane; t-butyl peroxybenzoate; benzoyl peroxide; tert-butyl peroxy acetate;2,5-dimethyl-2,5-bis(tert-butyl-peroxy)-hexyne-3;1,1-bis(tert-butyl-peroxy)-3,3,5-trimethylcyclohexane;1,1-bis(tert-butyl-peroxy)-cyclohexane; methyl ethyl ketone peroxide;2,5-dimethylhexyl-2,5-bis-peroxy-benzoate; tert-butyl-hydroperoxide;p-menthane hydroperoxide; p-chlorbenzoyl peroxide; tert-butylperoxyisobutyrate; hydroxyheptyl peroxide; and chlorohexanone peroxide.These are used alone or in mixed state, normally less than 10 parts byweight, preferably from 0.1 to 10 parts by weight per 100 parts byweight of EVA.

The organic peroxide is normally mixed to the EVA by an extruder or aroll mill or may be added to the EVA film by means of impregnation bydissolving the peroxide into organic solvent, plasticizer, or vinylmonomer.

In order to improve the properties of the EVA (such as mechanicalstrength, optical property, adhesive property, weatherability, blushingresistance, and crosslinking rate), a compound containing acryloxy groupor methacryloxy group and allyl group may be added into the EVA. Such acompound used for this purpose is usually acrylic acid or methacrylicacid derivative, for example, ester or amide thereof. Examples of esterresidues include alkyl group such as methyl, ethyl, dodecyl, stearyl,and lauryl and, besides such alkyl group, cycloxyhexyl group,tetrahydrofurfuryl group, aminoethyl group, 2-hydroethyl group,3-hydroxypropyl group, and 3-chloro-2-hydroxypropyl group. Ester withpolyfunctional alcohol such as ethylene glycol, triethylene glycol,polyethylene glycol, trimethylolpropane, or pentaerythritol may also beemployed. The typical amide is diacetone acrylamide.

More concretely, examples include compounds containing polyfunctionalester such as acrylic or methacrylic ester such as trimethylolpropane,pentaerythritol and glycerin, or containing allyl group such as triallylcyanurate, triallyl isocyanurate, diallyl phthalate, diallylisophthalate, and diallyl maleate. These are used alone or in the mixedstate, normally from 0.1 to 2 parts by weight, preferably from 0.5 to 5parts by weight per 100 parts by weight of EVA.

In case of the electromagnetic-wave shielding and light transmittingplate 1 of FIG. 1 when such cross-linked EVA is used, theelectromagnetic-wave shielding film 10 and the transparent substrate 2are laminated and temporally bonded via the intermediate adhesive layer4B with some pressure (this temporal adhesion allows re-adhesion, ifnecessary) and after that are pressurized and heated, thereby bondingthe electromagnetic-wave shielding film 10 and the transparent substrate2 with no air bubbles being captured therebetween as shown in FIG. 5.Therefore, the adhesive resin 4B′ of the intermediate adhesive layer 4Bcan intrude the small irregularities in the surface 14A of thetransparent adhesive agent 14 of the electromagnetic-wave shielding film10 so that the small irregularities are completely filled with theadhesive resin 4B′, thereby advantageously securely preventing lightscattering due to the irregularities.

To further securely prevent the light scattering due to the smallirregularities in the surface 14A of the transparent adhesive agent 14of the electromagnetic-wave shielding film 10 by means of the adhesiveresin 4B′ of the intermediate adhesive layer 4B, it is preferable thatthe refractive index of the transparent adhesive agent 14 is set to besubstantially equal to the refractive index of the adhesive resin 4B′after hardened so as to prevent reflection of light between the boundaryfaces of the transparent adhesive agent 14 and the adhesive resin 4B′.

Since the refractive index of the EVA as the adhesive resin 4B′ is onthe order of n=1.5, a transparent adhesive agent having a refractiveindex on the order of n=1.5 is preferably employed as the transparentadhesive agent 14. Besides the resin-type adhesive agent such as EVA orPVB, a transparent adhesive agent of epoxy series, acrylic series,urethane series, polyester series, or rubber series may also be employedas the transparent adhesive agent 14.

The thickness of each intermediate adhesive layer 4A, 4B is preferablyin a range from 10 to 1000 μm.

The intermediate adhesive layers 4A, 4B may further include, in smallamounts, ultraviolet ray absorbing agent, infrared ray absorbing agent,antioxidant, and/or paint processing aid. For adjusting the color of thefilter itself, they may further include coloring agent such as dye andpigment, and/or filler such as carbon black, hydrophobic silica, andcalcium carbonate.

It is also effective that the intermediate adhesive layers in sheetcondition are surfaced by corona discharge process, low temperatureplasma process, electron beam irradiation process, or ultravioletirradiation process as measures of improving the adhesive property.

The intermediate adhesive layers can be manufactured by first mixing theadhesive resin and the additives listed above, kneading them by anextruder or a roll, and after that, forming in a predeterminedconfiguration by means of a film forming method such as calendering,rolling, T-die extrusion, or inflation. During the film formation,embossing is provided for preventing the blocking between sheets andfacilitating the deaerating during compressed onto the transparent baseplate.

As another adhesive agent, pressure-sensitive adhesive as will bedescribed below may also be suitably employed as the intermediateadhesive layer 4A.

As the transparent self-adhesive 4D of the electromagnetic-waveshielding and light transmitting plate 1A of FIG. 2, transparentpressure-sensitive adhesive may be employed. For example, acrylicadhesives, and thermoplastic elastomers such as SBS and SEBS may also besuitably employed. Such pressure-sensitive adhesives may furthersuitably include tackifier, ultraviolet ray absorbing agent, coloringpigment, coloring dye, antioxidant, and/or sticking aid.

In case of using such transparent pressure-sensitive adhesive 4D, theelectromagnetic-wave shielding film 10 and the transparent substrate 2are laminated and temporally bonded via the transparentpressure-sensitive adhesive 4D with some pressure (this temporaladhesion allows re-adhesion, if necessary) and after that arepressurized and heated or depressurized and heated, thereby bonding theelectromagnetic-wave shielding film 10 and the transparent substrate 2with no air bubbles being captured therebetween as shown in FIG. 5.Therefore, the transparent pressure-sensitive adhesive 4D can intrudethe small irregularities in the surface 14A of the transparent adhesiveagent 14 of the electromagnetic-wave shielding film 10 so that the smallirregularities are completely filled with the transparentpressure-sensitive adhesive 4D, thereby advantageously securelypreventing light scattering due to the irregularities.

The transparent pressure-sensitive adhesive 4D allows re-adhesion andcan bond strongly the electromagnetic-wave shielding film 10 and thetransparent substrate 2 together without capturing air bubbles betweentheir boundary faces.

It is preferable that the transparent pressure-sensitive adhesive 4D isdirectly applied to a conductive foil surface pattern-etched on theelectromagnetic-wave shielding film 10.

To further securely prevent the light scattering due to the smallirregularities in the surface 14A of the transparent adhesive agent 14of the electromagnetic-wave shielding film 10 by means of thetransparent pressure-sensitive adhesive 4D, it is preferable that therefractive index of the transparent adhesive agent 14 is set to besubstantially equal to the refractive index of the transparentpressure-sensitive adhesive 4D so as to prevent reflection of lightbetween the boundary faces of the transparent adhesive agent 14 and thetransparent pressure-sensitive adhesive 4D.

Since the refractive index of the acrylic series, urethane series, EVAseries, PVB series, silicone series, and rubber series as thetransparent pressure-sensitive adhesive or adhesive agent 4D isgenerally on the order of n=1.5, a transparent adhesive agent having arefractive index on the order of n=1.5 is preferably employed as thetransparent adhesive agent 14. The transparent adhesive agent 14 havingsuch a refractive index may be of acrylic series, urethane series, andrubber series. In case of using epoxy series, polyester series as thetransparent pressure-sensitive adhesive or adhesive agent 4D, since therefractive index of the epoxy series and polyester series is on theorder of n=1.6-1.65, an adhesive agent having a refractive index on theorder of n=1.6-1.65 is preferably employed as the transparent adhesiveagent 14. The transparent adhesive agent 14 having such a refractiveindex may be of epoxy series and polyester series.

The electromagnetic-wave shielding film 10 may be directly bonded to thetransparent substrate 2 as shown in FIG. 1 and FIG. 2 and may be bondedto the transparent substrate 2 via another film.

Examples listed above as the transparent pressure-sensitive adhesive 4Dmay be employed as the pressure-sensitive adhesive 4C of thenear-infrared ray blocking film 5. The transparent pressure-sensitiveadhesive 4D or the pressure-sensitive adhesive 4C may be previouslyapplied on the electromagnetic-wave shielding film 10 or thenear-infrared ray blocking film 5 to have a thickness of 5-100 μm bycoating or lamination and, after that, the electromagnetic-waveshielding film 10 or the near-infrared ray blocking film 5 may beattached to the transparent substrate or another film.

The near-infrared ray blocking film 5 is preferably laminated on thetransparent substrate 2 by using the pressure-sensitive adhesive 4C.This is because the near-infrared ray blocking film 5 is sensitive toheat so as not to withstand heat at temperature for crosslinking(130-150° C.). Low-temperature crosslinkable EVA (the temperature forcrosslinking on the order of 70-130° C.) can be used for bonding thenear-infrared ray blocking film 5 to the transparent substrate 2.

Each second and first conductive sticky tape 7, 8 is formed, as shown inFIGS. 1 and 2, by laying a conductive pressure-sensitive adhesive layer7B, 8B, in which conductive particles are dispersed, on one surface of ametal foil 7A, 8A. The pressure-sensitive adhesive layers 7B, 8B may beacrylic adhesive, rubber adhesive, silicone adhesive, or epoxy orphenolic resin containing hardener.

Conductive materials of any type having good electrical continuities maybe employed as the conductive particles to be dispersed in thepressure-sensitive adhesive layers 7B, 8B. Examples include metallicpowder of, for example, copper, silver, and nickel, and resin or ceramicpowder coated with such a metal as mentioned above. There is no specificlimitation on its configuration so that the particles may have anyconfiguration such as scale-like, dendritic, granular, or pellet-likeconfiguration.

The content of the conductive particles is preferably 0.1-15% by volumerelative to the polymer composing the pressure-sensitive adhesive layers7B, 8B and the average particle size is preferably 0.1-100 μm. Bylimiting the content and the particle size as mentioned above, theconductive particles are prevented from being agglomerated, therebyobtaining good conduction.

The metal foils 7A, 8A as the substrates of the conductive sticky tapes7, 8 may be made of metal such as copper, silver, nickel, aluminum, orstainless steel and normally has a thickness of 1-100 μm.

The pressure-sensitive adhesive layers 7B, 8B are made of mixture inwhich the aforementioned adhesive and conductive particles are mixeduniformly in a predetermined ratio, and can be easily formed by applyingthe mixture onto the metallic foil using a roll coater, a die coater, aknife coater, a micabar coater, a flow coater, a spray coater or thelike.

The thickness of each pressure-sensitive adhesive layer 7B, 8B isnormally in a range from 5 to 100 μm.

To manufacture the electromagnetic-wave shielding and light transmittingplate 1 as shown in FIG. 1, for example, the antireflection film 3, theelectromagnetic-wave shielding film 10, the transparent substrate 2, thenear-infrared ray blocking film 5 with the pressure-sensitive adhesive4C, the intermediate adhesive layers 4A, 4B, and the first and secondconductive sticky tapes 8, 7 are first prepared. The first conductivesticky tape 8 is previously bonded to the peripheries of theelectromagnetic-wave shielding film 10. Then, the antireflection film 3,the electromagnetic-wave shielding film 10 with the first conductivesticky tape 8, and the transparent substrate 2 are laminated with theintermediate adhesive layers 4A, 4B interposed therebetween,respectively and then heated with being compressed under the hardeningcondition of the intermediate adhesive layers 4A, 4B to unite them.After that, the near-infrared ray blocking film 5 is laminated to thelaminated body with the pressure-sensitive adhesive 4C. Then, the secondconductive sticky tape 7 is attached to the peripheries of the laminatedbody and is bonded and fixed according to a hardening method, such asthermo compression bonding, suitable for the pressure-sensitive adhesivelayers 7B, 8B of the employed conductive sticky tapes 7, 8.

To manufacture the electromagnetic-wave shielding and light transmittingplate 1A as shown in FIG. 2, for example, the antireflection film 3, theelectromagnetic-wave shielding film 10, the transparent substrate 2, thenear-infrared ray blocking film 5 with the pressure-sensitive adhesive4C, the intermediate adhesive layer 4A, the transparentpressure-sensitive adhesive 4D, and the first and second conductivesticky tapes 8, 7 are first prepared. The transparent pressure-sensitiveadhesive 4D is previously applied to one surface of theelectromagnetic-wave shielding film 10 and the first conductive stickytape 8 is also previously bonded to the peripheries ofelectromagnetic-wave shielding film 10. Then, the electromagnetic-waveshielding film 10 with the first conductive sticky tape 8 and thetransparent pressure-sensitive adhesive 4D thereon is laid on and bondedto the transparent substrate 2. After that, the antireflection film 3 islaid on the laminated body via the intermediate adhesive layer 4A, andthey are heated with being compressed under the hardening condition ofthe intermediate adhesive layer 4A to unite them. After that, thenear-infrared ray blocking film 5 is laid on and bonded to the laminatedbody with the pressure-sensitive adhesive 4C. Then, the secondconductive sticky tape 7 is attached to the peripheries of the laminatedbody and is bonded and fixed according to a hardening method, such asthermo compression bonding or decompression heating, suitable for thepressure-sensitive adhesive layers 7B, 8B of the employed conductivesticky tapes 7, 8.

When cross-linkable conductive sticky tapes are used as the conductivesticky tapes 7, 8, the cross-linkable conductive sticky tapes are bondedto the electromagnetic-wave shielding film and the laminated body bytackiness of the pressure-sensitive adhesive layers 7B, 8B thereof (thistemporal adhesion allows re-adhesion, if necessary) and then heated orradiated with ultraviolet with some pressures, if necessary. Theultraviolet radiation may be performed with heating. The cross-linkableconductive sticky tape may be partially bonded by partially heating orradiating ultraviolet.

The thermo compression bonding can be easily conducted by a normal heatsealer. As one of compression and heating methods, a method may beemployed that the laminated body bonded with the cross-linkableconductive sticky tape is inserted into a vacuum bag which is thenvacuumed and after that is heated. Therefore, the bonding operation isquite easy.

The bonding condition in case of thermal cross-linking depends on thetype of crosslinking agent (organic peroxide) to be employed. Thecross-linking is conducted normally at a temperature from 70 to 150° C.,preferably from 70 to 130° C. and normally for 10 seconds to 120minutes, preferably 20 seconds to 60 minutes.

In case of optical cross-linking, various light sources emitting inultraviolet to visible range may be employed. Examples include anextra-high pressure, high pressure, or low pressure mercury lamp, achemical lamp, a xenon lamp, a halogen lamp, a Mercury halogen lamp, acarbon arc lamp, an incandescent lamp, and a laser radiation. The periodof radiation is not limited because it depends on the type of lamp andthe strength of the light source, but normally in a range from dozens ofseconds to dozens of minutes. In order to aid the cross-linking,ultraviolet may be radiated after previously heating to 40-120° C.

The pressure for bonding should be suitably selected and is preferably5-50 kg/cm², particularly 10-30 kg/cm².

The electromagnetic-wave shielding and light transmitting plates 1, 1Awith the conductive sticky tapes 7, 8 mentioned above can be quiteeasily built in a body of equipment and can provide good electriccontinuity between the electromagnetic-wave shielding film 10 and thebody of equipment through the first and second conductive sticky tapes7, 8 on four sides of the plate only by fitting into the body, therebyexhibiting high electromagnetic-wave shielding function. In addition,excellent near infrared ray blocking capability can be obtained becauseof the existence of the near-infrared ray blocking film 5. Further,since only a single piece of the transparent substrate 2 is used, theplate is thin and light. Since both the surfaces of the transparentsubstrate 2 are covered by the films 3, 5, respectively, theelectromagnetic-wave shielding and light transmitting plate has aneffect of preventing the transparent substrate 2 from being broken andan effect of preventing the scattering of broken pieces of thetransparent substrate 2 even if broken.

Since the electromagnetic-wave shielding film 10 is formed bypattern-etching a conductive foil such as the copper foil 11, the designof the etching pattern can be suitably changed, whereby goodelectromagnetic-wave shielding property and good light transmittingfunction are both obtained and the moire phenomenon is prevented. Theelectromagnetic-wave shielding film 10 has the light absorbing layer 12and has small irregularities formed in the surface of the lightabsorbing layer 12 by surface roughening. Further, irregularities in thetransparent adhesive agent 14 formed by transfer of the smallirregularities are filled with the transparent pressure-sensitiveadhesive 4B, thereby providing high antireflection effect and obtaininga distinct image having high contrast.

The electromagnetic-wave shielding and light transmitting plates shownin FIGS. 1 and 2 have been described by way of example ofelectromagnetic-wave shielding and light transmitting plates accordingto the first aspect of the present invention and the present inventionis not limited by the shown examples.

With reference to FIGS. 7A-7F, an exemplary method of manufacturing anelectromagnetic-wave shielding film to be used in anelectromagnetic-wave shielding and light transmitting plate of thesecond aspect of the present invention will be described.

For example, a copper foil 11 is prepared as a conductive foil (FIG. 7A)and the copper foil 11 is bonded to a transparent substrate such as aPET (polyethylene terephthalate) film 13 by a transparent adhesive agent14 (FIG. 7B).

Pattern-etching is conducted on the thus obtained laminated film topartially remove the copper foil 11 (FIG. 7C).

Then, a light absorbing layer 12 is formed on the surface of thepattern-etched copper foil 11 (FIG. 7D). As a forming method of thislight absorbing layer 12, there is a method of making a film of a copperalloy such as Cu—Ni and, after that, blackening a surface of the film bytreatment with acid or alkali. The blackened surface subjected to thissurface treatment is roughened. The surface roughness Rz can becontrolled according to the treatment condition. Alternatively, thelight absorbing layer 12 can be formed by applying a light absorbing inkonto the copper foil 11 and hardening the ink. Examples of the lightabsorbing ink used here include carbon ink, nickel ink, and inks such asdark color organic pigments. Then, the light absorbing layer 12 issubjected to a matting process to form small irregularities bymechanically roughening, for example, shot blasting the surface 12Athereof or chemically roughening the surface 12A using acid or alkali,alternatively, by applying the ink which is previously mixed with theinorganic or organic fine particles so as to form a film originallyhaving roughened surface (FIG. 7E). The thickness of the light absorbinglayer 12 varies depending on the blackening material and/or theconductivity, but it is preferable that the thickness is in a range from1 nm to 10 μm in order to sufficient electromagnetic-wave shieldingproperty without losing its conductivity. The level of roughness of thesurface 12A is preferably in a range from 0.1 to 20 μm as surfaceroughness Rz in order to sufficiently prevent the light scattering withexcellent antireflection efficiency.

After that, a transparent pressure-sensitive adhesive is applied on thecopper-foil-side surface of the thus obtained copper/PET laminatedetched film 10 a so as to form a coating layer 15, thereby obtaining anelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A (FIG. 7F).

The kind, the thickness, the pattern etching method, and the etchedpattern of the conductive foil composing the electromagnetic-waveshielding film are the same as those described with regard to theaforementioned method of manufacturing the electromagnetic-waveshielding film to be used in the electromagnetic-wave shielding andlight transmitting plate of the first aspect.

The kind and the thickness of the transparent substrate film to whichthe metal foil such as the copper foil 11 is bonded and the transparentadhesive agent for bonding the transparent substrate film and the metalfoil are also the same as mentioned above.

As the transparent pressure-sensitive adhesive forming the coating layer15 on the copper/PET laminated etched film 10 a, various transparentpressure-sensitive adhesive may be employed. For example, acrylicadhesives, and thermoplastic elastomers such as SBS and SEBS may besuitably employed. Such pressure-sensitive adhesives may furthersuitably include tackifier, ultraviolet ray absorbing agent, coloringpigment, coloring dye, antioxidant, and/or sticking aid.

It is preferable that the refractive index of the transparent adhesiveagent 14 is substantially equal to the refractive index of thetransparent pressure-sensitive adhesive of the coating layer 15 so as toprevent reflection of light between boundary faces of the transparentadhesive agent 14 and the transparent pressure-sensitive adhesive of thecoating layer 15.

Since the refractive index of the acrylic series, silicone series as thetransparent pressure-sensitive adhesive forming the coating layer 15 isgenerally on the order of n=1.5, a transparent adhesive agent having arefractive index on the order of n=1.5 is preferably employed as thetransparent adhesive agent 14. Examples of the transparent adhesiveagent 14 having such a refractive index include transparent adhesiveagents of acrylic series, urethane series, and rubber series.

The thickness of the coating layer 15 made of the transparentpressure-sensitive adhesive is preferably in a range from 1 to 100 μm.

The coating layer 15 of the transparent pressure-sensitive adhesive isapplied to expose the peripheries of the copper foil 11 to which aconductive sticky tape as will be described later is attached formanufacturing the electromagnetic-wave shielding and light transmittingplate.

Hereinafter, with reference to FIG. 6, an embodiment of theelectromagnetic-wave shielding and light transmitting plate according tothe second aspect will be described in detail.

FIG. 6 is a schematic sectional view showing an embodiment of theelectromagnetic-wave shielding and light transmitting plate according tothe second aspect of the present invention.

The electromagnetic-wave shielding and light transmitting plate 1B ofFIG. 6 comprises an antireflection film 3 as the front-most layer, anelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A, an intermediate adhesive layer 4B as adhesive agent, atransparent substrate 2, and a near-infrared ray blocking film 5 with apressure-sensitive adhesive layer 4C as the rear-most layer, whereinthey are laminated together to form a laminated body. A conductivesticky tape 7 (hereinafter, referred to as “second conductive stickytape”) is bonded to cover the peripheral ends of the laminated body andmargins along the edges of the front surface and the rear surfacethereof near the peripheral ends thereof to unite them. The size of theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A is substantially equal to the size of the transparentsubstrate 2 and a conductive sticky tape 8 (hereinafter, referred to as“first conductive sticky tape”) is bonded to and wound around theperipheral ends of the laminated body to extend from one surface to theother surface of the laminated body composed of the electromagnetic-waveshielding film with pressure-sensitive adhesive layer 10A, theintermediate adhesive layer 4B, and the transparent substrate 2. Thefirst conductive sticky tape 8 is preferably arranged all around theperipheries of the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A. However, the first conductivesticky tape may be arranged partially, for example, may be arranged onlyon two peripheries opposite to each other.

In the electromagnetic-wave shielding and light transmitting plate 1B,the antireflection film 3 is slightly smaller than theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A or the transparent substrate 2 so that the peripheries of theantireflection film 3 are slightly (preferably by 3-20 mm, particularly5-10 mm) back off from the peripheries of the electromagnetic-waveshielding film with pressure-sensitive adhesive layer 10A or thetransparent substrate 2 so that the first conductive sticky tape 8arranged around the peripheries of the electromagnetic-wave shieldingfilm with pressure-sensitive adhesive layer 10A is not covered by theantireflection film 3. Therefore, the second conductive sticky tape 7 isdirectly attached to the first conductive sticky tape 8, therebysecuring the electric continuity of the electromagnetic-wave shieldingfilm with pressure-sensitive adhesive layer 10A through the first andsecond conductive sticky tapes 8, 7.

The near-infrared ray blocking film 5 with the pressure-sensitiveadhesive 4C is also slightly smaller than the transparent substrate 2 sothat the peripheries of the near-infrared ray blocking film 5 with thepressure-sensitive adhesive 4C are slightly (preferably by 3-20 mm,particularly 5-10 mm) back off from the peripheries of the transparentsubstrate 2.

In this embodiment, none of the peripheries of the antireflection film 3and the near-infrared ray blocking film 5 with the pressure-sensitiveadhesive 4C is covered by the second conductive sticky tape 7. However,these may be located inside of and covered by the second conductivesticky tape 7. In the electromagnetic-wave shielding and lighttransmitting plate 1B of FIG. 6, it is necessary to establish theelectric continuity between the first conductive sticky tape 8 and thesecond conductive sticky tape 7. Therefore, the antireflection film 3must be smaller than the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A and the transparent substrate 2 sothat its peripheries are thus back off from the peripheries of theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A or the transparent substrate 2. On the other hand, thenear-infrared ray blocking film 5 with the pressure-sensitive adhesive4C may have the same size as the transparent substrate 2.

It is preferable that all peripheries of the antireflection film 3 arepreferably back off from the peripheries of the electromagnetic-waveshielding film with pressure-sensitive adhesive layer 10A or thetransparent substrate 2. However, when the first conductive sticky tape8 is attached to only a part of the peripheries, for example, twoperipheries opposite to each other, only the corresponding peripheriesmay be back off and the second conductive sticky tape 7 may be attachedto only the corresponding peripheries.

To manufacture the electromagnetic-wave shielding and light transmittingplate 1B as shown in FIG. 6, for example, the antireflection film 3, theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A, the transparent substrate 2, the near-infrared ray blockingfilm 5 with the pressure-sensitive adhesive 4C, the intermediateadhesive layer 4B, and the first and second conductive sticky tapes 8, 7are first prepared. The electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A and the transparent substrate 2are previously laminated via the intermediate adhesive layer 4B, andthen heated with being compressed or heated with being decompressedunder the hardening condition of the intermediate adhesive layer tounite them.

Then, the first conductive sticky tape 8 is bonded to the peripheries ofthe thus obtained laminated body. After that, the antireflection film 3is pressed against the coating layer 15 made of the transparentpressure-sensitive adhesive of the electromagnetic-wave shielding filmwith pressure-sensitive adhesive layer 10A so that the antireflectionfilm 3 is bonded to the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A. Then, the near-infrared rayblocking film 5 is laminated to the laminated body with thepressure-sensitive adhesive 4C. After that, the second conductive stickytape 7 is attached to the peripheries of the laminated body and isbonded and fixed according to a hardening method, such as thermocompression bonding or decompression heating, suitable for thepressure-sensitive adhesive layers 7B, 8B of the employed conductivesticky tapes 7, 8.

When cross-linkable conductive sticky tapes are used as the conductivesticky tapes 7, 8, the cross-linkable conductive sticky tapes are bondedby tackiness of the pressure-sensitive adhesive layers 7B, 8B thereof(this temporal adhesion allows re-adhesion, if necessary) and thenheated or radiated with ultraviolet with some pressures or with keepingits decompressed state, if necessary. The ultraviolet radiation may beperformed with heating. The cross-linkable conductive sticky tape may bepartially bonded by partially heating or radiating ultraviolet.

The thermo compression bonding can be easily conducted by a normal heatsealer. As one of compression and heating methods, a pressurizing andheating method may be employed that the laminated body bonded with thecross-linkable conductive sticky tape is inserted into a pressurizedchamber such as an autoclave and is heated, or a vacuuming and heatingmethod may be employed that the laminated body as mentioned above isinserted into a vacuum bag which is then vacuumed and after that isheated. Therefore, the bonding operation is quite easy.

The bonding condition in case of thermal cross-linking depends on thetype of crosslinking agent (organic peroxide) to be employed. Thecross-linking is conducted normally at a temperature from 70 to 150° C.,preferably from 70 to 130° C. and normally for 10 seconds to 120minutes, preferably 20 seconds to 60 minutes.

In case of optical cross-linking, various light sources emitting inultraviolet to visible range may be employed. Examples include anextra-high pressure, high pressure, or low pressure mercury lamp, achemical lamp, a xenon lamp, a halogen lamp, a Mercury halogen lamp, acarbon arc lamp, an incandescent lamp, and a laser radiation. The periodof radiation is not limited because it depends on the type of lamp andthe strength of the light source, but normally in a range from dozens ofseconds to dozens of minutes. In order to aid the cross-linking,ultraviolet may be radiated after previously heating to 40-120° C.

The pressure for bonding should be suitably selected and is preferably5-50 kg/cm², particularly 10-30 kg/cm².

The structure (material, thickness etc.) of the transparent substrate 2,the structure (material, lamination arrangement, thickness etc.) of theantireflection film 3, the structure (material, lamination arrangement,thickness etc.) of the near-infrared ray blocking film 5, the kind andthickness of the thermosetting resin forming the intermediate adhesivelayer 4B bonding the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A and the transparent substrate 2,and the structure (material, thickness etc.) of the conductive stickytapes 7, 8 are the same as those as described with reference to theelectromagnetic-wave shielding and light transmitting plate according tothe first aspect.

As mentioned above, the intermediate adhesive layer 4B is preferablymade of cross-linkable EVA. In case of using such intermediate adhesivelayer 4B, the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A is laminated and temporally bondedto the transparent substrate 2 via the intermediate adhesive layer 4Bwith some pressure (this temporal adhesion allows re-adhesion, ifnecessary) and after that are pressurized and heated or depressurizedand heated, thereby bonding the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A and the transparent substrate 2with no air bubbles being captured therebetween.

Also in the electromagnetic-wave shielding and light transmitting plate1B of FIG. 6, the near-infrared ray blocking film 5 is preferablylaminated on the transparent substrate 2 by using the pressure-sensitiveadhesive 4C. This is because the near-infrared ray blocking film 5 issensitive to heat so as not to withstand heat at temperature forcrosslinking (130-150° C.). Low-temperature crosslinkable EVA (thetemperature for crosslinking on the order of 70-130° C.) can be used forbonding the near-infrared ray blocking film 5 to the transparentsubstrate 2.

The intermediate adhesive layer 4B may further include, in smallamounts, ultraviolet ray absorbing agent, infrared ray absorbing agent,antioxidant, and/or paint processing aid. For adjusting the color of thefilter itself, it may further include coloring agent such as dye andpigment, and/or filler such as carbon black, hydrophobic silica, andcalcium carbonate.

It is also effective that the intermediate adhesive layer in sheetcondition is surfaced by corona discharge process, low temperatureplasma process, electron beam irradiation process, or ultravioletirradiation process as measures of improving the adhesive property.

The intermediate adhesive layer 4B can be manufactured by first mixingthe adhesive resin and the additives listed above, kneading them by anextruder or a roll, and after that, forming in a predeterminedconfiguration by means of a film forming method such as calendering,rolling, T-die extrusion, or inflation. During the film formation,embossing is provided for preventing the blocking between sheets andfacilitating the deaerating during compressed onto the transparent baseplate.

Besides the aforementioned adhesive agent, pressure-sensitive adhesivemay also be suitably employed as the intermediate adhesive layer 4B. Asthis pressure-sensitive adhesive and the pressure-sensitive adhesive 4Cof the near-infrared ray blocking film 5, acrylic adhesives,thermoplastic elastomers such as SBS and SEBS may also be suitablyemployed. Such pressure-sensitive adhesives may further suitably includetackifier, ultraviolet ray absorbing agent, coloring pigment, coloringdye, antioxidant, and/or sticking aid. The pressure-sensitive adhesivemay be previously applied on the transparent substrate 2 or thenear-infrared ray blocking film 5 to have a thickness of 5-100 μm bycoating or lamination and, after that, the transparent substrate 2 orthe near-infrared ray blocking film 5 with the pressure-sensitiveadhesive may be attached to the transparent substrate or another film.

Since the electromagnetic-wave shielding and light transmitting plate 1Bof FIG. 6 also has the conductive sticky tapes 7, 8 attached thereto,the electromagnetic-wave shielding and light transmitting plate 1B canbe quite easily built in a body of equipment and can provide goodelectric continuity between the electromagnetic-wave shielding film 10Aand the body of equipment through the first and second conductive stickytapes 7, 8 just by fitting into the body, thereby exhibiting highelectromagnetic-wave shielding function. In addition, excellent nearinfrared ray blocking capability can be obtained because of theexistence of the near-infrared ray blocking film 5. Further, since onlya single piece of the transparent substrate 2 is used, the plate is thinand light. Since both the surfaces of the transparent substrate 2 arecovered by the films 3, 5, respectively, the electromagnetic-waveshielding and light transmitting plate has an effect of preventing thetransparent substrate 2 from being broken and an effect of preventingthe scattering of broken pieces of the transparent substrate 2 even ifbroken.

Since the electromagnetic-wave shielding film with pressure-sensitiveadhesive layer 10A is formed by pattern-etching a conductive foil suchas the copper foil 11, the design of the etching pattern can be suitablychanged, whereby good electromagnetic-wave shielding function and goodlight transmitting property are both obtained and the moire phenomenonis prevented. The electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10A has the light absorbing layer 12and has small irregularities formed in the surface of the lightabsorbing layer 12 by surface roughening. Further, the irregularitiesare filled with the transparent pressure-sensitive adhesive, therebyproviding high antireflection effect and obtaining a distinct imagehaving high contrast.

That is, as shown in FIG. 8, the coating layer 15 of the transparentpressure-sensitive adhesive completely fills the irregularities by thecopper foil 11 and the light absorbing layer 12 formed on the substratefilm 13 and the transparent adhesive agent 14 of theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10A, thereby securely preventing light scattering due to theirregularities.

To further securely prevent the light scattering by means of thetransparent pressure-sensitive adhesive, it is preferable that therefractive index of the transparent pressure-sensitive adhesive is setto be substantially equal to the refractive index of the transparentadhesive agent 14 so as to prevent reflection of light between theboundary faces of the coating layer 15 of the transparentpressure-sensitive adhesive and the transparent adhesive agent 14 asmentioned above.

The electromagnetic-wave shielding and light transmitting plate shown inFIG. 6 has been described by way of example of electromagnetic-waveshielding and light transmitting plates according to the second aspectof the present invention and the present invention is not limited by theshown examples.

For example, the copper/PET laminated etched film 10 a as theelectromagnetic-wave shielding film and the antireflection film 3 may bebonded to each other by a previously formed coating layer 15 of thetransparent pressure-sensitive adhesive or by an intermediate adhesivelayer as mentioned above. In this case, the refractive index of theadhesive resin after hardened of the intermediate adhesive layer to beused is preferably substantially equal to the refractive index of thesubstrate film 13 for preventing the reflection of light between theseboundary faces.

With reference to FIGS. 10A-10Q an exemplary method of manufacturing anelectromagnetic-wave shielding film to be used in anelectromagnetic-wave shielding and light transmitting plate of the thirdaspect of the present invention will be described.

For example, a copper foil 11 is prepared as a conductive foil (FIG.10A) and a light absorbing layer 12 is formed on one surface of thecopper foil 11 (FIG. 10B). The light absorbing layer 12 is subjected toa matting process to form small irregularities by roughening the surface12A thereof (FIG. 10C).

Then, the copper foil 11 on which the light absorbing layer 12 is formedand treated by the matting process to have a matte surface is bonded atits matte surface side to a transparent substrate film such as a PET(polyethylene terephthalate) film 13 with a transparent adhesive agent14 (FIGS. 10D, 10E).

Pattern etching is conducted on the thus obtained laminated filmaccording to the normal method, whereby the copper foil 11 with thelight absorbing layer 12 formed thereon is partially removed so as toobtain a copper/PET laminated etched film 10 b as theelectromagnetic-wave shielding film (FIG. 10F).

Exposed surface 14A of the transparent adhesive agent 14 of thecopper/PET laminated etched film 10 b has irregularities correspondingto the small irregularities, formed by the matting process, of the lightabsorbing layer 12. A coating layer 15 is formed on the surface havingthe irregularities by applying a transparent pressure-sensitiveadhesive, thereby obtaining an electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B (FIG. 10G).

The forming method of the light absorbing layer 12, the matting method,the thickness of the light absorbing layer 12, and the surface roughnessof the surface 12A are the same as those described with regard to theaforementioned method of manufacturing the electromagnetic-waveshielding film to be used in the electromagnetic-wave shielding andlight transmitting plate of the first aspect.

As the transparent pressure-sensitive adhesive forming the coating layer15, various transparent pressure-sensitive adhesives may be employed.For example, acrylic adhesives, thermoplastic elastomers such as SBS andSEBS may also be suitably employed. Such pressure-sensitive adhesivesmay further suitably include tackifier, ultraviolet ray absorbing agent,coloring pigment, coloring dye, antioxidant, and/or sticking aid.

By forming the coating layer 15 of the transparent pressure-sensitiveadhesive, the transparent pressure-sensitive adhesive can intrude thesmall irregularities in the surface 14A of the transparent adhesiveagent 14 so that the small irregularities are completely filled with thetransparent pressure-sensitive adhesive, thereby advantageously securelypreventing light scattering due to the irregularities.

To further securely prevent the light scattering due to the smallirregularities in the surface 14A of the transparent adhesive agent 14by means of the transparent pressure-sensitive adhesive, it ispreferable that the refractive index of the transparent adhesive agent14 is set to be substantially equal to the refractive index of thetransparent pressure-sensitive adhesive of the coating layer 15 so as toprevent reflection of light between boundary faces of the transparentadhesive agent 14 and the transparent pressure-sensitive adhesive of thecoating layer 15.

Since the refractive index of the acrylic series, silicone series as thetransparent pressure-sensitive adhesive forming the coating layer 15 isgenerally on the order of n=1.5, a transparent adhesive agent having arefractive index on the order of n=1.5 is preferably employed as thetransparent adhesive agent 14. Examples of the transparent adhesiveagent 14 having such a refractive index include transparent adhesiveagents of acrylic series, urethane series, and rubber series.

The thickness of the coating layer 15 made of the transparentpressure-sensitive adhesive is preferably in a range from 1 to 100 μmmore preferably in a range from 2 to 50 μm because neither a too thicklayer nor a too thin layer can not conduct well adhesion when bonded tothe transparent substrate as will be described later.

The coating layer 15 of the transparent pressure-sensitive adhesive isapplied to expose the peripheries of the copper foil 11 to which aconductive sticky tape as will be described later is attached formanufacturing the electromagnetic-wave shielding and light transmittingplate.

The kind, the thickness, the pattern etching method, and the etchedpattern of the conductive foil composing the electromagnetic-waveshielding film are the same as those described with regard to theaforementioned method of manufacturing the electromagnetic-waveshielding film to be used in the electromagnetic-wave shielding andlight transmitting plate of the first aspect.

The kind and the thickness of the transparent substrate film to whichthe metal foil such as the copper foil 11 is attached and thetransparent adhesive agent for bonding the transparent substrate filmand the metal foil are also the same as mentioned above.

Hereinafter, with reference to FIG. 9, an embodiment of the method ofmanufacturing the electromagnetic-wave shielding and light transmittingplate using the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B mentioned above will be describedin detail.

FIG. 9 is a schematic sectional view showing an embodiment of theelectromagnetic-wave shielding and light transmitting plate manufacturedaccording to the present invention.

The electromagnetic-wave shielding and light transmitting plate 1C ofFIG. 9 comprises an antireflection film 3 as the front-most layer, anelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B, a transparent substrate 2, and a near-infrared ray blockingfilm 5 as the rear-most layer, wherein they are laminated together withan intermediate adhesive layer 4A, a transparent pressure-sensitiveadhesive of the coating layer 15, and a pressure-sensitive adhesive 4Cas adhesive agents to form a laminated body. A conductive sticky tape 7(hereinafter, referred to as “second conductive sticky tape”) is bondedto cover the peripheral ends of the laminated body and margins along theedges of the front surface and the rear surface thereof near theperipheral ends thereof. The size of the electromagnetic-wave shieldingfilm with pressure-sensitive adhesive layer 10B is substantially equalto the size of the transparent substrate 2 and a conductive sticky tape8 (hereinafter, referred to as “first conductive sticky tape”) is bondedto and wound around the peripheral ends of the electromagnetic-waveshielding film to extend from one surface where the copper foil 11 isformed to the other surface at the peripheries thereof. The firstconductive sticky tape 8 is preferably arranged all around theperipheries of the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B. However, the first conductivesticky tape may be arranged partially, for example, may be arranged onlyon two peripheries opposite to each other.

In the electromagnetic-wave shielding and light transmitting plate 1C,the antireflection film 3 and the intermediate adhesive layer 4A underthe antireflection film 3 are slightly smaller than theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B or the transparent substrate 2 so that the peripheries of theantireflection film 3 and the intermediate adhesive layer 4A areslightly (preferably by 3-20 mm, particularly 5-10 mm) back off from theperipheries of the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B or the transparent substrate 2 sothat the first conductive sticky tape 8 arranged around the peripheriesof the electromagnetic-wave shielding film with pressure-sensitiveadhesive layer 10B is not covered by the antireflection film 3 or theintermediate adhesive layer 4A. Therefore, the second conductive stickytape 7 is directly attached to the first conductive sticky tape 8,thereby securing the electric continuity of the electromagnetic-waveshielding film with pressure-sensitive adhesive layer 10B through thefirst and second conductive sticky tapes 8, 7.

The near-infrared ray blocking film 5 with the pressure-sensitiveadhesive 4C is also slightly smaller than the transparent substrate 2 sothat the peripheries of the near-infrared ray blocking film 5 with thepressure-sensitive adhesive 4C are slightly (preferably by 3-20 mm,particularly 5-10 mm) back off from the peripheries of the transparentsubstrate 2.

In this embodiment, none of the peripheries of the antireflection film3, the intermediate adhesive layer 4A, and the near-infrared rayblocking film 5 with the pressure-sensitive adhesive 4C is covered bythe second conductive sticky tape 7. However, these may be locatedinside of and covered by the second conductive sticky tape 7. In theelectromagnetic-wave shielding and light transmitting plate 1C of FIG.9, it is necessary to establish the electric continuity between thefirst conductive sticky tape 8 and the second conductive sticky tape 7.Therefore, the antireflection film 3 and the intermediate adhesive layer4A must be smaller than the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B and the transparent substrate 2 sothat their peripheries are thus back off from the peripheries of theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B or the transparent substrate 2. On the other hand, thenear-infrared ray blocking film 5 with the pressure-sensitive adhesive4C may have the same size as the transparent substrate 2.

It is preferable that all peripheries of the antireflection film 3 andthe intermediate adhesive layer 4A are preferably back off from theperipheries of the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B or the transparent substrate 2.However, when the first conductive sticky tape 8 is attached to only apart of the peripheries, for example, two peripheries opposite to eachother, only the corresponding peripheries may be back off and the secondconductive sticky tape 7 may be attached to only the correspondingperipheries.

To manufacture the electromagnetic-wave shielding and light transmittingplate 1C as shown in FIG. 9, for example, the antireflection film 3, theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B, the transparent substrate 2, the near-infrared ray blockingfilm 5 with the pressure-sensitive adhesive 4C, the intermediateadhesive layer 4A, and the first and second conductive sticky tapes 8, 7are first prepared. The first conductive sticky tape 8 is previouslybonded to the peripheries of the electromagnetic-wave shielding filmwith pressure-sensitive adhesive layer 10B. The electromagnetic-waveshielding film with pressure-sensitive adhesive layer 10B with the firstconductive sticky tape 8 is bonded to the transparent substrate 2.

As for this bonding, the coating layer 15 of the transparentpressure-sensitive adhesive of the electromagnetic-wave shielding filmwith pressure-sensitive adhesive layer 10B is attached and laminated tothe transparent substrate 2 and temporally bonded with some pressure(this temporal adhesion allows re-adhesion, if necessary) and after thatare pressurized and heated or depressurized and heated, thereby bondingthe electromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B and the transparent substrate 2 with no air bubbles beingcaptured therebetween as shown in FIG. 11. Therefore, the transparentpressure-sensitive adhesive 15′ can intrude the small irregularities inthe surface 14A of the transparent adhesive agent 14 of theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B so that the small irregularities are completely filled withthe transparent pressure-sensitive adhesive 15′, thereby advantageouslysecurely preventing light scattering due to the irregularities. Bysetting the refractive index of the transparent adhesive agent 14 to bethe same as the refractive index of the transparent pressure-sensitiveadhesive 15′, the light scattering can be further securely prevented.

After that, the antireflection film 3 is laid via the intermediateadhesive layer 4A on the transparent substrate 2 with theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B attached thereto and then heated with being compressed orheated with being decompressed under the hardening condition of theintermediate adhesive layer 4A to unite them. After that, thenear-infrared ray blocking film 5 is laminated to the laminated bodywith the pressure-sensitive adhesive 4C. Then, the second conductivesticky tape 7 is attached to the peripheries of the laminated body andis bonded and fixed by pressurizing and heating or depressurizing andheating according to a hardening method suitable for thepressure-sensitive adhesive layers 7B, 8B of the employed conductivesticky tapes 7, 8.

When cross-linkable conductive sticky tapes are used as the conductivesticky tapes 7, 8, the cross-linkable conductive sticky tapes are bondedto the electromagnetic-wave shielding film and the laminated body bytackiness of the pressure-sensitive adhesive layers 7B, 8B thereof (thistemporal adhesion allows re-adhesion, if necessary) and then heated orradiated with ultraviolet while being compressed or being decompressed,if necessary. The ultraviolet radiation may be performed with heating.The cross-linkable conductive sticky tape may be partially bonded bypartially heating or radiating ultraviolet.

The thermo compression bonding can be easily conducted by a normal heatsealer. As one of compression and heating methods, a pressurizing andheating method may be employed that the laminated body bonded with thecross-linkable conductive sticky tape is inserted into a pressurizedchamber such as an autoclave and is heated, or a vacuuming and heatingmethod may be employed that the laminated body as mentioned above isinserted into a vacuum bag which is then vacuumed and after that isheated. Therefore, the bonding operation is quite easy.

The bonding condition in case of thermal cross-linking depends on thetype of crosslinking agent (organic peroxide) to be employed. Thecross-linking is conducted normally at a temperature from 70 to 150° C.,preferably from 70 to 130° C. and normally for 10 seconds to 120minutes, preferably 20 seconds to 60 minutes.

In case of optical cross-linking, various light sources emitting inultraviolet to visible range may be employed. Examples include anextra-high pressure, high pressure, or low pressure mercury lamp, achemical lamp, a xenon lamp, a halogen lamp, a Mercury halogen lamp, acarbon arc lamp, an incandescent lamp, and a laser radiation. The periodof radiation is not limited because it depends on the type of lamp andthe strength of the light source, but normally in a range from dozens ofseconds to dozens of minutes. In order to aid the cross-linking,ultraviolet may be radiated after previously heating to 40-120° C.

The pressure for bonding should be suitably selected and is preferably5-50 kg/cm², particularly 10-30 kg/cm².

The structure (material, thickness etc.) of the transparent substrate 2,the structure (material, lamination arrangement, thickness etc.) of theantireflection film 3, the structure (material, lamination arrangement,thickness etc.) of the near-infrared ray blocking film 5, the kind andthickness of the thermosetting resin forming the intermediate adhesivelayer 4A bonding the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B and the antireflection film 3, andthe structure (material, thickness etc.) of the conductive sticky tapes7, 8 are the same as those as described with reference to theelectromagnetic-wave shielding and light transmitting plate according tothe first aspect.

Besides the aforementioned adhesive agents, the agents listed above asthe transparent pressure-sensitive adhesive to be used in theelectromagnetic-wave shielding film with pressure-sensitive adhesivelayer 10B may also be suitably used as the intermediate adhesive layer4A.

The agents listed above as the transparent pressure-sensitive adhesiveto be used in the electromagnetic-wave shielding film withpressure-sensitive adhesive layer 10B may also be suitably used as thepressure-sensitive adhesive 4C of the near-infrared ray blocking film 5.The pressure-sensitive adhesive 4C may be previously applied on thenear-infrared ray blocking film 5 to have a thickness of 5-100 μm bycoating or lamination and, after that, the near-infrared ray blockingfilm 5 with the pressure-sensitive adhesive may be attached to thetransparent substrate or another film.

The near-infrared ray blocking film 5 is preferably laminated on thetransparent substrate 2 by using the pressure-sensitive adhesive 4C.This is because the near-infrared ray blocking film 5 is sensitive toheat so as not to withstand heat at temperature for crosslinking(130-150° C.). Low-temperature crosslinkable EVA (the temperature forcrosslinking on the order of 70-130° C.) can be used for bonding thenear-infrared ray blocking film 5 to the transparent substrate 2.

As shown in FIG. 9, the electromagnetic-wave shielding and lighttransmitting plate 1C with the conductive sticky tapes 7, 8 can be quiteeasily built in a body of equipment and can provide good electriccontinuity between the electromagnetic-wave shielding film 10B and thebody of equipment through the first and second conductive sticky tapes7, 8 only by fitting into the body, thereby exhibiting highelectromagnetic-wave shielding function. In addition, excellent nearinfrared ray blocking capability can be obtained because of theexistence of the near-infrared ray blocking film 5. Further, since onlya single piece of the transparent substrate 2 is used, the plate is thinand light. Since both the surfaces of the transparent substrate 2 arecovered by the films 3, 5, respectively, the electromagnetic-waveshielding and light transmitting plate has an effect of preventing thetransparent substrate 2 from being broken and an effect of preventingthe scattering of broken pieces of the transparent substrate 2 even ifbroken.

Since the electromagnetic-wave shielding film 10B is formed bypattern-etching a conductive foil such as the copper foil 11, the designof the etching pattern can be suitably changed, whereby goodelectromagnetic-wave shielding function and good light transmittingfunction are both obtained and the moire phenomenon is prevented. Theelectromagnetic-wave shielding film 10B has the light absorbing layer 12and has small irregularities formed in the surface of the lightabsorbing layer 12 by surface roughening. Further, irregularities in thetransparent adhesive agent 14 formed by transfer of the smallirregularities are filled with the transparent pressure-sensitiveadhesive 15′, thereby providing high antireflection effect and obtaininga distinct image having high contrast.

The electromagnetic-wave shielding and light transmitting plate shown inFIG. 9 has been described by way of example of electromagnetic-waveshielding and light transmitting plates to be manufactured in the methodof the present invention and the present invention is not limited by theshown examples.

The electromagnetic-wave shielding and light transmitting plates of thepresent invention and the electromagnetic-wave shielding and lighttransmitting plates to be manufactured in the method of the presentinvention as described in detail above are quite suitable for a frontfilter of PDP and a window of a place where a precision apparatus isinstalled, such as a hospital or a laboratory.

Hereinafter, embodiments of s display panel of the present inventionwill be described in detail with reference to FIGS. 12 and 13.

FIG. 12 is a schematic sectional view showing an embodiment of a displaypanel according to the fourth aspect of the present invention and FIG.13 is a schematic sectional view showing an embodiment of a displaypanel according to the fifth aspect of the present invention.

A display panel 30A of FIG. 12 comprises an antireflection film 3 as thefront-most layer, a copper/PET laminated etched film 10 as theelectromagnetic-wave shielding film (the electromagnetic-wave shieldingfilm 10 has the same structure as the electromagnetic-wave shieldingfilm used in the electromagnetic-wave shielding and light transmittingplate according to the first aspect and is manufactured by theprocedures shown in FIG. 3A through FIG. 3F), a near-infrared rayblocking film 5, and a PDP body 20, wherein they are laminated andunited by using intermediate adhesive layers 4A, 4B, 4C as the adhesiveagents so as to form a laminated body. A conductive sticky tape 7(second conductive sticky tape) is bonded to cover the peripheral endsof the laminated body and margins along the edges of the front surfaceand the rear surface thereof near the peripheral ends thereof.

A display panel 30B of FIG. 13 comprises an antireflection film 3 as thefront-most layer, a copper/PET laminated etched film 10 a as theelectromagnetic-wave shielding film (the electromagnetic-wave shieldingfilm 10 a has the same structure as the copper/PET laminated etched film10 a before the formation of the coating layer 15 of transparentpressure-sensitive adhesive of the electromagnetic-wave shielding filmused in the electromagnetic-wave shielding and light transmitting plateaccording to the second aspect and is manufactured by the proceduresshown in FIG. 7A through FIG. 7E), a near-infrared ray blocking film 5,and a PDP body 20, wherein they are laminated and united by usingintermediate adhesive layers 4A, 4B, 4C as the adhesive agents so as toform a laminated body. A conductive sticky tape 7 is bonded to cover theperipheral ends of the laminated body and margins along the edges of thefront surface and the rear surface thereof near the peripheral endsthereof.

The size of the electromagnetic-wave shielding film 10 (10 a) issubstantially equal to the size of the PDP body 20 and a conductivesticky tape 8 (hereinafter, referred to as “first conductive stickytape”) is bonded to and wound around the peripheral ends of theelectromagnetic-wave shielding film to extend from one surface to theother surface thereof. The first conductive sticky tape 8 is preferablyarranged all around the peripheries of the electromagnetic-waveshielding film 10 (10 a). However, the first conductive sticky tape maybe arranged partially, for example, may be arranged only on twoperipheries opposite to each other.

In the display panel 30A (30B), the antireflection film 3 and theintermediate adhesive layer 4A under the antireflection film 3 areslightly smaller than the electromagnetic-wave shielding film 10 (10 a)so that the peripheries of the antireflection film 3 and theintermediate adhesive layer 4A are slightly (preferably by 3-20 mm,particularly 5-10 mm) back off from the peripheries of theelectromagnetic-wave shielding film 10 (10 a) so that the firstconductive sticky tape 8 arranged around the peripheries of theelectromagnetic-wave shielding film 10 (10 a) is not covered by theantireflection film 3 and the intermediate adhesive layer 4A. Therefore,the second conductive sticky tape 7 is directly attached to the firstconductive sticky tape 8, thereby securing the electric continuity ofthe electromagnetic-wave shielding film 10 (10 a) through the first andsecond conductive sticky tapes 8, 7.

In this embodiment, none of the peripheries of the antireflection film 3and the intermediate adhesive layer 4A covers the second conductivesticky tape 7. However, these may be arranged outside the secondconductive sticky tape 7 to cover the second conductive sticky tape 7.In the display panel 30A (30B) of FIG. 12 (FIG. 13), it is necessary toestablish the electric continuity between the first conductive stickytape 8 and the second conductive sticky tape 7. Therefore, theantireflection film 3 and the intermediate adhesive layer 4A must besmaller than the electromagnetic-wave shielding film 10 (10 a) so thattheir peripheries are thus back off from the peripheries of theelectromagnetic-wave shielding film 10 (10 a).

It is preferable that all peripheries of the antireflection film 3 andthe intermediate adhesive layer 4A are preferably back off from theperipheries of the electromagnetic-wave shielding film 10 (10 a).However, when the first conductive sticky tape 8 is attached to only apart of the peripheries, for example, two peripheries opposite to eachother, only the corresponding peripheries may be back off and the secondconductive sticky tape 7 may be attached to only the correspondingperipheries.

The structure (material, lamination arrangement, thickness etc.) of theantireflection film 3, the structure (material, lamination arrangement,thickness etc.) of the near-infrared ray blocking film 5, the kind andthickness of the thermosetting resin forming the intermediate adhesivelayers 4A, 4B, 4C bonding the antireflection film 3, theelectromagnetic-wave shielding film 10 (10 a), the near-infrared rayblocking film 5 and the PDP body 20, and the structure (material,thickness etc.) of the conductive sticky tapes 7, 8 are the same asthose as described with reference to the electromagnetic-wave shieldingand light transmitting plate according to the first aspect.

As the PDP body 20, a PDP as shown in FIG. 16 may be employed.

Similarly to the electromagnetic-wave shielding and light transmittingplate of the present invention, when such cross-linked EVA is used asthe thermosetting resin forming the intermediate adhesive layers 4A-4C,the components of the display panel 30A (30B) are laminated andtemporally bonded via the intermediate adhesive layers 4A-4C with somepressure (this temporal adhesion allows re-adhesion, if necessary) and,after that, are pressurized and heated, thereby bonding the members withno air bubbles being captured therebetween. Therefore, in the displaypanel 30A of FIG. 12, the electromagnetic-wave shielding film 10 and thenear-infrared ray blocking film 5 are laminated and temporally bondedvia the intermediate adhesive layer 4B and, after that, are pressurizedand heated, thereby bonding the electromagnetic-wave shielding film 10and the near-infrared ray blocking film 5 with no air bubbles beingcaptured therebetween as shown in FIG. 14. Accordingly, the adhesiveresin 4B′ of the intermediate adhesive layer 4B can intrude the smallirregularities in the surface 14A of the transparent adhesive agent 14of the electromagnetic-wave shielding film 10 so that the smallirregularities are completely filled with the adhesive resin 4B′,thereby advantageously securely preventing light scattering due to theirregularities.

To further securely prevent the light scattering due to the smallirregularities in the surface 14A of the transparent adhesive agent 14of the electromagnetic-wave shielding film 10 by means of the adhesiveresin 4B′ of the intermediate adhesive layer 4B, it is preferable thatthe refractive index of the transparent adhesive agent 14 is set to besubstantially equal to the refractive index of the adhesive resin 4B′after hardened so as to prevent reflection of light between the boundaryfaces of the transparent adhesive agent 14 and the adhesive resin 4B′.

Since the refractive index of the EVA as the adhesive resin 4B′ is onthe order of n=1.5, a transparent adhesive agent having a refractiveindex on the order of n=1.5 is preferably employed as the transparentadhesive agent 14. Examples of the transparent adhesive agent 14 havingsuch a refractive index include transparent adhesive agents of acrylicseries, urethane series, epoxy series, and rubber series.

Similarly, in the display panel 30B of FIG. 13, the electromagnetic-waveshielding film 10 a and the antireflection film 3 are laminated andtemporally bonded via the intermediate adhesive layer 4A and, afterthat, are pressurized and heated, thereby bonding theelectromagnetic-wave shielding film 10 a and the antireflection film 3with no air bubbles being captured therebetween as shown in FIG. 15. Theadhesive resin 4A′ of the intermediate adhesive layer 4A completelyfills the irregularities by the copper foil 11 and the light absorbinglayer 12 formed on the substrate film 13 and the transparent adhesiveagent 14 of the electromagnetic-wave shielding film 10 a, therebysecurely preventing light scattering due to the irregularities.

It is preferable that the refractive index of the transparent adhesiveagent 14 is set to be substantially equal to the refractive index of theadhesive resin 4A′ after hardened so as to reduce the reflection oflight between the boundary faces between the adhesive resin 4A′ of theintermediate adhesive layer 4A and transparent adhesive agent 14 of theelectromagnetic-wave shielding film 10 a.

Since the refractive index of the EVA as the adhesive resin 4A′ is onthe order of n=1.5, a transparent adhesive agent having a refractiveindex on the order of n=1.5 is preferably employed as the transparentadhesive agent 14. Examples of the transparent adhesive agent 14 havingsuch a refractive index include transparent adhesive agents of acrylicseries, urethane series, and rubber series.

Besides the aforementioned adhesive agent, a transparentpressure-sensitive adhesive may also be suitably employed as theintermediate adhesive layers 4A, 4B, 4C. As this transparentpressure-sensitive adhesive, acrylic adhesives, and thermoplasticelastomers such as SBS and SEBS may also be suitably employed. Suchtransparent pressure-sensitive adhesives may further suitably includetackifier, ultraviolet ray absorbing agent, coloring pigment, coloringdye, antioxidant, and/or sticking aid. The transparentpressure-sensitive adhesive may be previously applied on theantireflection film 3, the electromagnetic-wave shielding films 10, 10a, or the near-infrared ray blocking film 5 to have a thickness of 5-100μm by coating or lamination and, after that, the films may be attachedto the PDP body 20 or another film.

It is preferable that the near-infrared ray blocking film 5 is laminatedand bonded by using a pressure-sensitive adhesive. This is because thenear-infrared ray blocking film 5 is sensitive to heat so as not towithstand heat at temperature for crosslinking (130-150° C.).Low-temperature crosslinkable EVA (the temperature for crosslinking onthe order of 70-130° C.) can be used for bonding the near-infrared rayblocking film 5.

To manufacture the display panel 30A (30B) as shown in FIG. 12 (FIG.13), for example, the antireflection film 3, the electromagnetic-waveshielding film 10 (10 a), the near-infrared ray blocking film 5, the PDPbody 20, the intermediate adhesive layers 4A, 4B, 4C, and the first andsecond conductive sticky tapes 8, 7 are first prepared. The firstconductive sticky tape 8 is previously bonded to the peripheries of theelectromagnetic-wave shielding film 10 (10 a). Then, the antireflectionfilm 3, the electromagnetic-wave shielding film 10 (10 a) with the firstconductive sticky tape 8, and the near-infrared ray blocking film 5, andthe PDP body 20 are laminated with the intermediate adhesive layers 4A,4B, 4C interposed therebetween, respectively and then heated with beingcompressed under the hardening condition of the intermediate adhesivelayers to unite them. After that, the second conductive sticky tape 7 isattached to the peripheries of the laminated body and is bonded andfixed according to a hardening method, such as thermo compressionbonding, suitable for the pressure-sensitive adhesive layers 7B, 8B ofthe employed conductive sticky tapes 7, 8.

When cross-linkable conductive sticky tapes are used as the conductivesticky tapes 7, 8, the cross-linkable conductive sticky tapes are bondedto the electromagnetic-wave shielding film and the laminated body bytackiness of the pressure-sensitive adhesive layers 7B, 8B thereof (thistemporal adhesion allows re-adhesion, if necessary) and then heated orradiated with ultraviolet with some pressures, if necessary. Theultraviolet radiation may be performed with heating. The cross-linkableconductive sticky tape may be partially bonded by partially heating orradiating ultraviolet.

The thermo compression bonding can be easily conducted by a normal heatsealer. As one of compression and heating methods, a pressurizing andheating method may be employed that the laminated body bonded with thecross-linkable conductive sticky tape is inserted into a vacuum bagwhich is then vacuumed and after that is heated. Therefore, the bondingoperation is quite easy.

The bonding condition in case of thermal cross-linking depends on thetype of crosslinking agent (organic peroxide) to be employed. Thecross-linking is conducted normally at a temperature from 70 to 150° C.,preferably from 70 to 130° C. and normally for 10 seconds to 120minutes, preferably 20 seconds to 60 minutes.

In case of optical cross-linking, various light sources emitting inultraviolet to visible range may be employed. Examples include anextra-high pressure, high pressure, or low pressure mercury lamp, achemical lamp, a xenon lamp, a halogen lamp, a Mercury halogen lamp, acarbon arc lamp, an incandescent lamp, and a laser radiation. The periodof radiation is not limited because it depends on the type of lamp andthe strength of the light source, but normally in a range from dozens ofseconds to dozens of minutes. In order to aid the cross-linking,ultraviolet may be radiated after previously heating to 40-120° C.

The pressure for bonding should be suitably selected and is preferably5-50 kg/cm², particularly 10-30 kg/cm².

The display panel 30A (30B) with the conductive sticky tapes 7, 8attached thereto can be quite easily built in a body of equipment andcan provide good electric continuity between the electromagnetic-waveshielding film 10 (10 a) and the body of equipment through the first andsecond conductive sticky tapes 7, 8 only by fitting the display panelinto the body, thereby exhibiting high electromagnetic-wave shieldingfunction. Since there is the antireflection film 3 at the front surfaceside of the electromagnetic-wave shielding film 10 (10 a), excellentantireflection effect can be obtained because of the antireflection film3. In addition, excellent near infrared ray blocking capability can beobtained because of the existence of the near-infrared ray blocking film5, thereby preventing occurrence of malfunction of remote control.Further, since the display panel is made by laminating and bonding thefilm onto the PDP body 20, the display panel is thin and light. Sincethe front surface of the PDP body 20 is covered by the antireflectionfilm 3 as the front-most layer, the electromagnetic-wave shielding film10 (10 a), and the near-infrared ray blocking film 5, the PDP body isprotected to have improved impact resistance and an effect of preventingthe PDP body from being broken and an effect of preventing thescattering of broken pieces of the PDP body 20 even if broken.

Since the electromagnetic-wave shielding film 10 (10 a) is formed bypattern-etching a conductive foil such as the copper foil 11, the designof the etching pattern can be suitably changed, whereby goodelectromagnetic-wave shielding function and good light transmittingproperty are both obtained and the moire phenomenon is prevented. Theelectromagnetic-wave shielding film 10 (10 a) has the light absorbinglayer 12 and has small irregularities formed in the surface of the lightabsorbing layer 12 by surface roughening. Further, in the display panel30A using the electromagnetic-wave shielding film 10, irregularities inthe transparent adhesive agent 14 formed by transfer of the smallirregularities of the film 10 are filled with the adhesive resin,thereby providing high antireflection effect and obtaining a distinctimage having high contrast. Further, in the display panel 30B using theelectromagnetic-wave shielding film 10 a, the irregularities of thelight absorbing layer 12 and the copper foil 11 are filled with theadhesive resin, thereby providing high antireflection effect andobtaining a distinct image having high contrast.

The display panels shown in FIGS. 12 and 13 have been described by wayof examples of display panels of the present invention and the presentinvention is not limited by the shown examples.

INDUSTRIAL APPLICABILITY

As described in detail, according to the present invention, anelectromagnetic-wave shielding and light transmitting plate is providedwhich not only has excellent electromagnetic-wave shielding function butalso provides high antireflection effect and has a high level oftransparency and a high level of visibility, thus is capable ofobtaining a distinct image, and can be suitably used as a front filterfor a PDP.

According to the display panel of the present invention, functions suchas the electromagnetic-wave shielding function can be applied to adisplay panel itself by uniting a display panel body such as a PDP andan electromagnetic-wave shielding film. In addition, the improvement inproductivity and reduction in cost can be achieved by reducing theweight, the thickness, and the number of parts of the display panel.Further, the occurrence of malfunction of the remote control can beprevented. Moreover, since the electromagnetic-wave shielding film notonly has excellent electromagnetic-wave shielding function but alsoprovides high antireflection effect and has a high level of transparencyand a high level of visibility, the display panel can provide a distinctimage.

1. An electromagnetic-wave shielding and light transmitting plate havingat least an electromagnetic-wave shielding film and a transparentsubstrate which are laminated and united, wherein saidelectromagnetic-wave shielding film comprising a transparent substratefilm and a conductive foil which is bonded to the transparent substrateside surface of said transparent substrate film with a transparentadhesive agent, and is applied with pattern etching, said conductivefoil has a light absorbing layer for antireflection provided on atransparent substrate film side surface of said conductive foil, and atransparent substrate film side surface of said light absorbing layer istreated by surface roughening, wherein the surface roughness Rz of theroughened surface of the light absorbing layer is in a range from 0.1 to20 μm, wherein the roughened surface is one of a shot blasted surface, achemically roughened surface using acid or alkali and an ink coveredsurface, the ink previously mixed with inorganic or organic fineparticles.
 2. An electromagnetic-wave shielding and light transmittingplate as claimed in claim 1, wherein said electromagnetic-wave shieldingfilm is bonded on the conductive foil side surface thereof to saidtransparent substrate with a thermosetting resin.
 3. Anelectromagnetic-wave shielding and light transmitting plate as claimedin claim 2, wherein said thermosetting resin is a cross-linkablethermosetting resin containing a cross linking agent.
 4. Anelectromagnetic-wave shielding and light transmitting plate as claimedin claim 2, wherein said thermosetting resin after hardened has arefractive index substantially equal to the refractive index of saidtransparent adhesive agent of said electromagnetic-wave shielding film.5. An electromagnetic-wave shielding and light transmitting plate asclaimed in claim 1, wherein said electromagnetic-wave shielding film isbonded on the conductive foil side surface thereof to the transparentsubstrate with a transparent pressure-sensitive adhesive.
 6. Anelectromagnetic-wave shielding and light transmitting plate as claimedin claim 5, wherein the transparent pressure-sensitive adhesive isdirectly applied on the surface of the pattern-etched conductive foil onsaid electromagnetic-wave shielding film.
 7. An electromagnetic-waveshielding and light transmitting plate as claimed in claim 5, whereinsaid transparent pressure-sensitive adhesive has a refractive indexsubstantially equal to the refractive index of said transparent adhesiveagent of said electromagnetic-wave shielding film.
 8. Anelectromagnetic-wave shielding and light transmitting plate as claimedin claim 1, wherein said electromagnetic-wave shielding and lighttransmitting plate comprises a laminated body formed by laminating anduniting a single piece of the transparent substrate with anantireflection film as the front-most layer, said electromagnetic-waveshielding film provided between the transparent substrate and theantireflection film, and a near-infrared ray blocking film providedbetween the electromagnetic-wave shielding film and the transparentsubstrate.
 9. An electromagnetic-wave shielding and light transmittingplate as claimed in claim 8, wherein said electromagnetic-wave shieldingand light transmitting plate comprises a laminated body formed bylaminating and uniting a single piece of the transparent substrate withthe antireflection film as the front-most layer, saidelectromagnetic-wave shielding film provided between the transparentsubstrate and the antireflection film, and the near-infrared rayblocking film provided on an opposite side of the transparent substrateas said electromagnetic-wave shielding film.
 10. An electromagnetic-waveshielding and light transmitting plate as claimed in claim 9, wherein afirst conductive tape is bonded to and wound around the peripheral endsof said transparent substrate and the electromagnetic-wave shieldingfilm bonded to the transparent substrate to extend from the frontsurface of the electromagnetic-wave shielding film to the rear surfaceof the transparent substrate, at least a portion of the peripheries ofsaid antireflection film is backed off from the corresponding peripheryof said electromagnetic-wave shielding film, and a second conductivetape is bonded to said laminated body to extend from edge portions ofthe front-most surface to edge portions of the rear-most surface throughthe peripheral ends of said laminated body.
 11. An electromagnetic-waveshielding and light transmitting plate as claimed in claim 8, wherein afirst conductive tape is bonded to and wound around the peripheral endsof the electromagnetic-wave shielding film to extend from one surface tothe other surface of the electromagnetic-wave shielding film, theperipheries of said antireflection film are at least partially backedoff from the peripheries of said electromagnetic-wave shielding film,and a second conductive tape is bonded to said laminated body to extendfrom edge portions of the front-most surface to edge portions of therear-most surface through the peripheral ends of said laminated body.